If you have read-only git-svn git cl would still try
to use svn commands, which would then fail. This
changes git cl to only use git-svn if the remote
svn repository use the svn:// protocol. It matches
how chromium works and it allowed me to upload a patch.

BUG=391430

R=iannucci

Review URL: https://codereview.chromium.org/344013005

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@281500 0039d316-1c4b-4281-b951-d872f2087c98