Use resource collector for the fencing -> stonith ordering

Use resource collector for the fencing -> stonith ordering

Change Ifef08033043a4cc90a6261e962d2fdecdf275650 moved the stonith
property definition to the pacemaker_master node. This means that the
Class['tripleo::fencing'] -> Class['pacemaker::stonith'] ordering
breaks on non-boostrap pacemaker nodes because the pacemaker::stonith
property is not defined there any longer.

Let's fix this by simply using a resource collector and set the ordering
on that instead of adding yet anoth if statement. Ordering on
enablement of stonith is actually more correct formally.

Tested this on a broken setup successfully.

Closes-Bug: #1712605
Change-Id: I616d340bdf75da9d9eb8b83b2e804dff3d07d58e