BZ #1086344 - Add Cinder service to HA hostgroup

https://bugzilla.redhat.com/show_bug.cgi?id=1086344

Adds Cinder to the HA controller host group. So far only iscsi backend
is supported. Note that iscsi backend requires cinder-volumes LVM
volume group to exist on the target machine. I don't think this will
be a handy configuration for HA host group in production (data saved
in the LVM iscsi backend is not really HA), but it is handy for
testing. The installation of cinder-volume service on the HA
controller is optional, switched off by default.

Gluster support should follow and it should also be made the default
backend.

(Also enables creation of Cinder DB in the hamysql::singlenodetest
class.)
BZ #1083781 - fetch glance user password from pacemaker::params

https://bugzilla.redhat.com/show_bug.cgi?id=1083781

Tweak to fetch glance_user_password from pacemaker::params instead of
taking it as a parameter in pacemaker::glance.
Merge pull request #159 from jistr/ha_cinder_2

BZ #1086344 - Add Cinder service to HA hostgroup
Use new gluster::api class on compute nodes for libgfapi access
Configure libgfapi access when cinder_backend_gluster is set

Setting qemu_allowed_storage_drivers=gluster in the nova config causes
libvirt/qemu to mount gluster volumes via libgfapi.