Dashboard - Blacklist last_alerted_revision on TestMetadata migration
Dashboard - Blacklist last_alerted_revision on TestMetadata migration

TBR=d3ffe0e065c2328e497bb32a07f4dcb29138ef5b@chromium.org

Bug: chromium:932564
Change-Id: Ib30937d92a0b314e70e44e46e303cd75759e60e6
Reviewed-on: https://chromium-review.googlesource.com/c/1474713
Reviewed-by: Simon Hatch <490a224d89645d3fea983d7189ce51bde0a00c1d@chromium.org>
Reviewed-by: Ben Hayden <d3ffe0e065c2328e497bb32a07f4dcb29138ef5b@chromium.org>
Commit-Queue: Simon Hatch <490a224d89645d3fea983d7189ce51bde0a00c1d@chromium.org>

catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult