Remove freeze as suggestion on git cl upload

Freeze command creates a commit, which then could be uploaded with git
cl upload.

R=gavinmak@google.com

Bug: 630822
Change-Id: I2fdc7bd8579f17680454b046ae80a473c6d420aa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3923515
Commit-Queue: Josip Sokcevic <sokcevic@google.com>
Reviewed-by: Gavin Mak <gavinmak@google.com>
Auto-Submit: Josip Sokcevic <sokcevic@google.com>
Commit-Queue: Gavin Mak <gavinmak@google.com>

git_common.py

@@ -847,8 +847,8 @@ def is_dirty_git_tree(cmd):
 
   dirty = get_dirty_files()
   if dirty:
-    w('Cannot %s with a dirty tree. Commit, freeze or stash your changes first.'
-      % cmd)
+    w('Cannot %s with a dirty tree. Commit%s or stash your changes first.' %
+      (cmd, '' if cmd == 'upload' else ', freeze'))
     w('Uncommitted files: (git diff-index --name-status HEAD)')
     w(dirty[:4096])
     if len(dirty) > 4096: # pragma: no cover