Add Glusterfs volume for keystone credential-keys.

Change-Id: Ife24619123ae962aac9d58dca4a5cdee125e26af
diff --git a/glusterfs/client/volume/keystone.yml b/glusterfs/client/volume/keystone.yml
index 7139029..822b61f 100644
--- a/glusterfs/client/volume/keystone.yml
+++ b/glusterfs/client/volume/keystone.yml
@@ -13,3 +13,9 @@
           user: keystone
           group: keystone
           opts: "defaults,backup-volfile-servers=${_param:glusterfs_node01_address}:${_param:glusterfs_node02_address}:${_param:glusterfs_node03_address}"
+        keystone-credential-keys:
+          path: /var/lib/keystone/credential-keys
+          server: ${_param:keystone_glusterfs_service_host}
+          user: keystone
+          group: keystone
+          opts: "defaults,backup-volfile-servers=${_param:glusterfs_node01_address}:${_param:glusterfs_node02_address}:${_param:glusterfs_node03_address}"