rbd: implement get_volume_stats()

Report raw capacity because replication level may change, and the
cluster may be used by more than one service. If the command fails for
any reason, return unknown capacity.

Change-Id: If6871124301b51e4768ea64c4d8e5109e0804db8
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Add LIO configuration for iSCSI initiators

LIO requires iSCSI initiator IQNs to be specified in an ACL to be
allowed to connect to the target. Currently this is only done for
the IQN of the initiator on the cinder-volume node.

This patch allows setting lio_initiator_iqns in cinder.conf to
provide access to other nodes.  (Remote Nova compute nodes.)

Change-Id: I7ddee542fcd3fba5b6f142ad15459c08cfedc9d2
Ensure volume exists before deleting.

fixes bug 1130744

Change-Id: I39152dd1caa5ab1b2cfbae56eaec8c8fa309669c
Merge "Add LIO configuration for iSCSI initiators"
Merge "rbd: implement get_volume_stats()"