Clarify OWNERS error if using TBR.

The message was previously not clear that if the entire CL has any change
to an OWNERS file, TBR will not apply.

Change-Id: Ib30a93f80196f45b02a29701faab7cf581e37f50
Reviewed-on: https://chromium-review.googlesource.com/1176321
Reviewed-by: Marc-Antoine Ruel <maruel@chromium.org>
Commit-Queue: Robert Sesek <rsesek@chromium.org>

presubmit_canned_checks.py

@@ -892,8 +892,8 @@ def CheckOwners(input_api, output_api, source_file_filter=None):
         output_fn('Missing %s for these files:\n    %s' %
                   (needed, '\n    '.join(sorted(missing_files))))]
     if input_api.tbr and affects_owners:
-      output_list.append(output_fn('Note that TBR does not apply to changes '
-                                   'that affect OWNERS files.'))
+      output_list.append(output_fn('The CL affects an OWNERS file, so TBR will '
+                                   'be ignored.'))
     if not input_api.is_committing:
       suggested_owners = owners_db.reviewers_for(missing_files, owner_email)
       owners_with_comments = []

tests/presubmit_unittest.py

@@ -2763,7 +2763,7 @@ class CannedChecksUnittest(PresubmitTestsBase):
         expected_output=re.compile(
             'Missing LGTM from an OWNER for these files:\n'
             '    foo\n'
-            '.*TBR does not apply to changes that affect OWNERS files.',
+            '.*The CL affects an OWNERS file, so TBR will be ignored.',
             re.MULTILINE))
 
   def testCannedCheckOwners_WithoutOwnerLGTM(self):