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
Merge "Add LIO configuration for iSCSI initiators"