It turns out a subsequent required step after a cold boot bootstrap is
notifying the cluster of the new bootstrap UUID.
The notify-bootstrapped action should be run on a different node than
the one which ran the bootstrap-pxc action.
This action will ensure the cluster converges on the correct bootstrap
UUID.
A subsequent patch stacked on this one will include tests for the new
cold boot actions.
Change-Id: Idee12d5f7e28498c5ab6ccb9605f751c6427ac30
Partial-Bug: #1744393