NFS: Revamp example, add nfs-common to debian saltbase

This ensures nfs-common is installed on GCE, and provides a more
functional explanation/example. I launched two replication controllers
so that there were busybox pods to poke around at the NFS volume, and
so that the later wget actually works (the original example would have
to work on the node, or need some other access to the container
network). After switching to two controllers, it actually makes more
sense to use PV claims, and it's probably a configuration that makes
more sense for indirection for NFS anyways.

examples/examples_test.go

@@ -306,9 +306,13 @@ func TestExampleObjectSchemas(t *testing.T) {
 			"wordpress":         &api.Pod{},
 		},
 		"../examples/nfs": {
-			"nfs-server-pod":     &api.Pod{},
+			"nfs-busybox-rc":     &api.ReplicationController{},
+			"nfs-server-rc":      &api.ReplicationController{},
 			"nfs-server-service": &api.Service{},
-			"nfs-web-pod":        &api.Pod{},
+			"nfs-pv":             &api.PersistentVolume{},
+			"nfs-pvc":            &api.PersistentVolumeClaim{},
+			"nfs-web-rc":         &api.ReplicationController{},
+			"nfs-web-service":    &api.Service{},
 		},
 		"../docs/user-guide/node-selection": {
 			"pod": &api.Pod{},