Handle unusual case in rebase-update where second rebase attempt works.

Previously we just added an assert here but better
to simply succeed in this case, while outputting
the intial failure message.

BUG=425696

Review URL: https://codereview.chromium.org/667793005

git-svn-id: http://src.chromium.org/chrome/trunk/tools/depot_tools@292687 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
Added orphaned compiled Python file checks.

There have been a handful of cases where orphaned compiled Python files (.pyc
files without an accompanying .py file) have been loaded preferentially by
the presubmit scripts, causing weird problems. This adds a check and a mode for
such files, either warning the user or deleting them.

BUG=None
TEST=local
  - Tested against local repository.

R=iannucci@chromium.org, szager@chromium.org

Review URL: https://codereview.chromium.org/621533002

git-svn-id: http://src.chromium.org/chrome/trunk/tools/depot_tools@292703 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
Fix handling of ast.Str object.

TBR=iannucci@chromium.org
BUG=

Review URL: https://codereview.chromium.org/686183003

git-svn-id: http://src.chromium.org/chrome/trunk/tools/depot_tools@292733 4ff67af0-8c30-449e-8e8b-ad334ec8d88c