assert_pacemaker() transforms node names to FQDN before comparison

Pacemaker returns it's status using FQDN on CentOS and short node
names on Ubuntu. It makes hard for comparison different node
name formats with always FQDN from nailgun.

Now output of pacemaker status converts into FQDN before comparison.

Change-Id: I73bdb208111e993ab0135cd7aded47e90a0f1b34
Closes-Bug:#1400169
(cherry picked from commit 81594361fd573e430a5b4add5b5bf1ed15f33c2e)
Merge "assert_pacemaker() transforms node names to FQDN before comparison" into stable/6.0