Fix for sorting alerts in dashboard based on revisions.
Fix for sorting alerts in dashboard based on revisions.

BUG=catapult:#3676

Review-Url: https://codereview.chromium.org/2956963002

catapult-project/catapult,catapult-project/catapult-csm,benschmaus/catapult,catapult-project/catapult-csm,catapult-project/catapult,catapult-project/catapult-csm,catapult-project/catapult,catapult-project/catapult,benschmaus/catapult,catapult-project/catapult,catapult-project/catapult-csm,catapult-project/catapult-csm,catapult-project/catapult,benschmaus/catapult,benschmaus/catapult,benschmaus/catapult,catapult-project/catapult-csm,benschmaus/catapult,catapult-project/catapult-csm,benschmaus/catapult,catapult-project/catapult