Add CinderBackupOptVolumes parameter

This adds a new parameter 'CinderBackupOptVolumes' to allow
cinder-backup to mount extra volumes.

Change-Id: Ide6d464be4a13457debfeceb61e5255c06b67808

deployment/cinder/cinder-common-container-puppet.yaml

@@ -35,6 +35,10 @@ parameters:
     default: []
     description: list of optional volumes to be mounted
     type: comma_delimited_list
+  CinderBackupOptVolumes:
+    default: []
+    description: list of optional volumes to be mounted
+    type: comma_delimited_list
   CinderVolumeOptEnvVars:
     default: {}
     description: hash of optional environment variables
@@ -235,6 +239,7 @@ outputs:
     value:
       list_concat:
         - *cinder_common_volumes
+        - {get_param: CinderBackupOptVolumes}
         -
           - /var/lib/kolla/config_files/cinder_backup.json:/var/lib/kolla/config_files/config.json:ro
           - /etc/iscsi:/var/lib/kolla/config_files/src-iscsid:ro