Automatic merge from submit-queue (batch tested with PRs 41104, 41245, 40722, 41439, 41502)

Change the etcd rollback tool to do rollback to 2.2.1 version.

I did some tests of it and for my 3-node cluster with 1 deployment it worked fine.

But before merging this, we should probably do way more testing (we should rerun tests that @mml was doing for the previous script).

@lavalamp @xiang90