Revert "Fetch the input commit ref when both ref and id are specified."

This reverts commit 72a245e4c6.

Reason for revert: crbug.com/1022617

Original change's description:
> Fetch the input commit ref when both ref and id are specified.
> 
> This causes --refs refs/head/master to be added to bot_update calls when
> the input build message contains a commit id and the refs/head/master
> ref. This is an effective no-op.
> 
> When bot_update clones a git repository, it results in HEAD referring to
> master in contrast to the non-clone case which results in a detached
> HEAD. This prevents fetching refs/heads/master, so detach the HEAD after
> cloning.
> 
> Bug: 922150
> Change-Id: I357a78305020218e9f5d350832a706b8f2b27967
> Recipe-Nontrivial-Roll: build
> Recipe-Nontrivial-Roll: build_limited_scripts_slave
> Recipe-Nontrivial-Roll: infra
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1900735
> Commit-Queue: Garrett Beaty <gbeaty@chromium.org>
> Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>

TBR=ehmaldonado@chromium.org,gbeaty@chromium.org

Change-Id: Ibd6c6ed272b0c98f82be50cefa521aaee0444f11
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 922150, 1022617
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1904099
Reviewed-by: Stephen Martinis <martiniss@chromium.org>
Commit-Queue: Stephen Martinis <martiniss@chromium.org>

recipes/README.recipes.md

@@ -56,7 +56,7 @@ Recipe module to ensure a checkout is consistent on a bot.
 
 Wrapper for easy calling of bot_update.
 
-— **def [deapply\_patch](/recipes/recipe_modules/bot_update/api.py#500)(self, bot_update_step):**
+— **def [deapply\_patch](/recipes/recipe_modules/bot_update/api.py#498)(self, bot_update_step):**
 
 Deapplies a patch, taking care of DEPS and solution revisions properly.
     
@@ -87,7 +87,7 @@ Args:
   step_test_data: a null function that returns test bot_update.py output.
     Use test_api.output_json to generate test data.
 
-— **def [get\_project\_revision\_properties](/recipes/recipe_modules/bot_update/api.py#477)(self, project_name, gclient_config=None):**
+— **def [get\_project\_revision\_properties](/recipes/recipe_modules/bot_update/api.py#475)(self, project_name, gclient_config=None):**
 
 Returns all property names used for storing the checked-out revision of
 a given project.
@@ -105,7 +105,7 @@ Returns (list of str): All properties that'll hold the checked-out revision
 
 &emsp; **@property**<br>&mdash; **def [last\_returned\_properties](/recipes/recipe_modules/bot_update/api.py#36)(self):**
 
-&mdash; **def [resolve\_fixed\_revision](/recipes/recipe_modules/bot_update/api.py#427)(self, bot_update_json, name):**
+&mdash; **def [resolve\_fixed\_revision](/recipes/recipe_modules/bot_update/api.py#425)(self, bot_update_json, name):**
 
 Set a fixed revision for a single dependency using project revision
 properties.

recipes/recipe_modules/bot_update/api.py

@@ -190,8 +190,6 @@ class BotUpdateApi(recipe_api.RecipeApi):
       # e.g. they want to force refs/heads/master at the config level.
       main_repo_path = self._get_commit_repo_path(in_commit, cfg)
       revisions[main_repo_path] = revisions.get(main_repo_path) or in_commit_rev
-      if in_commit.id and in_commit.ref:
-        refs = [in_commit.ref] + refs
 
     # Guarantee that first solution has a revision.
     # TODO(machenbach): We should explicitly pass HEAD for ALL solutions

recipes/recipe_modules/bot_update/examples/full.expected/basic.json

@@ -16,8 +16,6 @@
       "/path/to/tmp/json",
       "--revision",
       "src@2d72510e447ab60a9728aeea2362d8be2cbd7789",
-      "--refs",
-      "refs/heads/master",
       "--disable-syntax-validation"
     ],
     "env_suffixes": {

recipes/recipe_modules/bot_update/examples/full.expected/basic_luci.json

@@ -16,8 +16,6 @@
       "/path/to/tmp/json",
       "--revision",
       "src@2d72510e447ab60a9728aeea2362d8be2cbd7789",
-      "--refs",
-      "refs/heads/master",
       "--disable-syntax-validation"
     ],
     "env_suffixes": {

recipes/recipe_modules/bot_update/examples/full.expected/basic_with_branch_heads.json

@@ -16,8 +16,6 @@
       "/path/to/tmp/json",
       "--revision",
       "src@2d72510e447ab60a9728aeea2362d8be2cbd7789",
-      "--refs",
-      "refs/heads/master",
       "--with_branch_heads",
       "--disable-syntax-validation"
     ],

recipes/recipe_modules/bot_update/examples/full.expected/no_cp_checkout_HEAD.json

@@ -18,8 +18,6 @@
       "got_revision@src",
       "--revision",
       "src@HEAD",
-      "--refs",
-      "refs/heads/master",
       "--disable-syntax-validation"
     ],
     "env_suffixes": {

recipes/recipe_modules/bot_update/examples/full.expected/no_cp_checkout_a_specific_commit.json

@@ -18,8 +18,6 @@
       "got_revision@src",
       "--revision",
       "src@aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
-      "--refs",
-      "refs/heads/master",
       "--disable-syntax-validation"
     ],
     "env_suffixes": {

recipes/recipe_modules/bot_update/examples/full.expected/resolve_chromium_fixed_version.json

@@ -16,8 +16,6 @@
       "/path/to/tmp/json",
       "--revision",
       "src@2d72510e447ab60a9728aeea2362d8be2cbd7789",
-      "--refs",
-      "refs/heads/master",
       "--disable-syntax-validation"
     ],
     "env_suffixes": {

recipes/recipe_modules/bot_update/examples/full.expected/with_manifest_name.json

@@ -16,8 +16,6 @@
       "/path/to/tmp/json",
       "--revision",
       "src@2d72510e447ab60a9728aeea2362d8be2cbd7789",
-      "--refs",
-      "refs/heads/master",
       "--disable-syntax-validation"
     ],
     "env_suffixes": {

recipes/recipe_modules/bot_update/resources/bot_update.py

@@ -724,8 +724,6 @@ def _git_checkout(sln, sln_dir, revisions, refs, no_fetch_tags, git_cache_dir,
       if not path.isdir(sln_dir):
         git('clone', '--no-checkout', '--local', '--shared', mirror_dir,
             sln_dir)
-        # Detach HEAD to be consistent with the non-clone case
-        git('checkout', 'master', '--detach')
         _git_disable_gc(sln_dir)
       else:
         _git_disable_gc(sln_dir)