Creating user cinder in computes

The patch creates new classes system.linux.users.cinder and
system.nova.compute.volume.nfs The last one is supposed to be
included on nova-compute nodes is nfs backend is enabled to add
nova user to cinder group.

Change-Id: I720e1ecec0946ce37742d207161b03d5e4f0eb8a
Related-PROD: PROD-22772 (PROD:22772)
diff --git a/nova/compute/volume/nfs.yml b/nova/compute/volume/nfs.yml
new file mode 100644
index 0000000..8ff7266
--- /dev/null
+++ b/nova/compute/volume/nfs.yml
@@ -0,0 +1,13 @@
+# (ohryhorov): the class is created to be included in favour of creating
+# user cinder and add user nova to group cinder in all nova-compute nodes
+# if nfs backend is used.
+# PROD-22772
+classes:
+- system.linux.system.users.cinder
+parameters:
+  nova:
+    compute:
+      user:
+        groups:
+          - cinder
+          - libvirtd