Set bash as shell when executing mariadb recovery task
Set bash as shell when executing mariadb recovery task

Added 'executable' argument to the shell action in the
'Comparing seqno value' task in the cluster recovery playbook.

Change-Id: I3e96a4a76b44ffb558b9a41cde16e66a8d0fab1a
Closes-Bug: #1729603

dardelean/kolla-ansible,dardelean/kolla-ansible,dardelean/kolla-ansible