Allow override of galera promote timeout
This commit removes the hard coded value of pacemaker promote time out
(currently 300s), and allows operators to override it via:
tripleo::profile::pacemaker::database::mysql::promote_timeout
tripleo::profile::pacemaker::database::mysql_bundle::promote_timeout
Closes-Bug: #1883896
Change-Id: I96f5d349b94f05f4f66db6b85ba481deba0015d9
(cherry picked from commit 0606e22e24)