correctly.  Also fix git_cl.py.

BUG=None
TEST=Make sure that the -m command line option to gcl upload/git cl upload
does not add a new message to the rietveld issue.  The string associated to the
--message argument should only be used as the patchset title.

Review URL: https://chromiumcodereview.appspot.com/10384150

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@136922 0039d316-1c4b-4281-b951-d872f2087c98