Fix Docker Auth and our V2 registry paths to support library (i.e. namespace-less) repositories.

This support is placed behind a feature flag.

endpoints/bitbuckettrigger.py

@@ -8,7 +8,6 @@ from buildtrigger.bitbuckethandler import BitbucketBuildTrigger
 from endpoints.common import route_show_if
 from app import app
 from data import model
-from util.names import parse_repository_name
 from util.http import abort
 from auth.auth import require_session_login