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.
BZ#113272 - Cinder volume active/active should be avoided

https://bugzilla.redhat.com/show_bug.cgi?id=1132722

There's a bug reported against Cinder that if multiple cinder-volume
services are configured with the same backend storage and one
cinder-volume service goes down, its volumes are stranded - the other
cinder-volume services do not take over the management of these
volumes. Details on Launchpad [1].

The workaround is to set the "host" configuration option to the same
value for all cinder-volume services, so that they all appear as one,
and use active/passive HA for cinder-volume.

The side effect is that if we use iSCSI backend with local LVM data
storage for Cinder on the HA controllers, we can only use the disk
space on one of the controllers, not all (cinder-volume service will
run on only one controller). This should not be a problem because it
is not an expected production setup with HA controller - Cinder
backend setup using local LVM data storage on controllers wouldn't
provide HA anyway. If the user wants to scale out LVM data storage
backend, they can still use the Block Storage host group. This commit
only affects HA controller.

[1] https://bugs.launchpad.net/cinder/+bug/1322190
Merge pull request #167 from jeckersb/bz1062693

Use libgfapi for compute access to cinder volumes
BZ #1123296 - increase rabbitmq haproxy timeout

https://bugzilla.redhat.com/show_bug.cgi?id=1123296
Merge pull request #361 from jistr/cinder_volume_ha

BZ#113272 - Cinder volume active/active should be avoided
Merge pull request #365 from jeckersb/bz1123296

BZ #1123296 - increase rabbitmq haproxy timeout
BZ #1135732 - puppet dep cycle error with rbd glance backend

https://bugzilla.redhat.com/show_bug.cgi?id=1135732

fix rbd dependency cycle: remove explicit Package['python-ceph']
ordering.
Merge pull request #364 from cwolferh/rbd_dep_cycle_fix

fix rbd dependency cycle