Disable br-ex (or equivalent) to be created on compute nodes
Add initial base class for configuring pacemaker.

All other classes we add to use pacemaker to manage various services will go in
this module as well.
Merge pull request #131 from jguiditta/pacemaker_common

Add initial base class for configuring pacemaker.
Merge pull request #122 from gildub/neutron+fix-upstream-bridge-on-compute-nodes

Disable br-ex (or equivalent) to be created on compute nodes