Don't freak out if 'ignore_locks' options is not set.

BUG=406636
R=stip@chromium.org

Review URL: https://codereview.chromium.org/497293002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@291561 0039d316-1c4b-4281-b951-d872f2087c98

gclient_scm.py

@@ -805,7 +805,7 @@ class GitWrapper(SCMWrapper):
     else:
       depth = None
     mirror.populate(verbose=options.verbose, bootstrap=True, depth=depth,
-                    ignore_lock=options.ignore_locks)
+                    ignore_lock=getattr(options, 'ignore_locks', False))
     mirror.unlock()
 
   def _Clone(self, revision, url, options):