ceph-volume lvm.batch use 'ceph' as the cluster name with filestore

Custom cluster names are currently broken on ceph-volume, should get
addressed with http://tracker.ceph.com/issues/27210 which is out of
scope for these changes

Signed-off-by: Alfredo Deza <adeza@redhat.com>
(cherry picked from commit c148179)

src/ceph-volume/ceph_volume/tests/functional/batch/centos7/filestore/mixed-type-dmcrypt/group_vars/all

@@ -1,7 +1,7 @@
 ---
 
 ceph_dev: True
-cluster: test
+cluster: ceph
 public_network: "192.168.3.0/24"
 cluster_network: "192.168.4.0/24"
 monitor_interface: eth1