fix broken classes

these files are empty:
* linux/network/interface/bond_ovs_dvr.yml is not valid yaml
* glusterfs/cluster.yml is not valid yaml
* linux/network/interface/bond_vlan_dvr.yml is not valid yaml
* jenkins/master/single.yml is not valid yaml

Change-Id: I9c27d6ea41fcad0e14a28097eac7cfe540fb2983
diff --git a/glusterfs/cluster.yml b/glusterfs/cluster.yml
index e69de29..8a5c595 100644
--- a/glusterfs/cluster.yml
+++ b/glusterfs/cluster.yml
@@ -0,0 +1,2 @@
+classes:
+- service.glusterfs.server