Cinder-backup requires iscsid running on the same host

Cinder-backup containers require iscsid to mount iscsi volumes
to backup if the volumes are on different storage host.

Change-Id: Ifc0a30584a4f086b71278616d34bf87863d3e6e5
Closes-Bug: 1611330

ansible/inventory/all-in-one

@@ -161,6 +161,7 @@ storage
 # iSCSI
 [iscsid:children]
 compute
+storage
 
 [tgtd:children]
 storage

ansible/inventory/multinode

@@ -174,6 +174,7 @@ storage
 # iSCSI
 [iscsid:children]
 compute
+storage
 
 [tgtd:children]
 storage