Don't throw an error if not on stabilizing branch and give more information on exit.

cros_mark_as_stable.py

 #!/usr/bin/python
 
 # Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """This module uprevs a given package's ebuild to the next revision."""
 
 
 import fileinput
@@ skipping 108 matching lines @@
 
   Raises:
       OSError: Error occurred while pushing.
   """
 
   # TODO(sosa) - Add logic for buildbot to check whether other slaves have
   # completed and push this change only if they have.
 
   # Sanity check to make sure we're on a stabilizing branch before pushing.
   if not _CheckOnStabilizingBranch():
-    generate_test_report.Die('Expected %s to be on branch "%s"' %
-                             (os.getcwd(), _STABLE_BRANCH_NAME))
+    print 'Not on branch %s so no work found to push.  Exiting' % \
+        _STABLE_BRANCH_NAME
+    return
+
   description = _RunCommand('git log --format=format:%s%n%n%b ' +
                             gflags.FLAGS.tracking_branch + '..')
   description = 'Marking set of ebuilds as stable\n\n%s' % description
   merge_branch_name = 'merge_branch'
   _RunCommand('git remote update')
   _RunCommand('git checkout -b %s %s' % (
       merge_branch_name, gflags.FLAGS.tracking_branch))
   try:
     _RunCommand('git merge --squash %s' % _STABLE_BRANCH_NAME)
     _RunCommand('git commit -m "%s"' % description)
@@ skipping 229 matching lines @@
              'and reset the git repo yourself.' %
              (package_list[:index], overlay_directory))
       raise e
   elif command == 'push':
     _PushChange()
 
 
 if __name__ == '__main__':
   main(sys.argv)