message: Fix update-release-branch-fix.py
  This change ensures that the the script can handle
  commits with no committer in them. This will happen
  for some commits that are auto-generated during
  PRs.
diff: @@ -122,7 +122,7 @@ def get_commit_difference(repo):
  # Is the given commit the automatic merge commit from when merging a PR
  def is_pr_merge_commit(commit):
  - return commit.committer.login == 'web-flow' and len(commit.parents) > 1
  + return commit.committer is not None and commit.committer.login == 'web-flow' and len(commit.parents) > 1
  # Gets a copy of the commit message that should display nicely
  def get_truncated_commit_message(commit):
  