Defining volume_use_multipath for nova compute

The patch add possibility to use volume_use_multipath in
in libvirt for nova compute.

Change-Id: I35829191c23e6cae9a9fd78b97d7a5a83a165eb3
Related-PROD: PROD-24803 (PROD:24803)
diff --git a/README.rst b/README.rst
index f3c22f6..948f8ec 100644
--- a/README.rst
+++ b/README.rst
@@ -502,6 +502,16 @@
             address: 1.2.3.4
             port: 8776
 
+Define multipath for nova compute:
+
+.. code-block:: yaml
+
+    nova:
+      compute:
+        ....
+        libvirt:
+          volume_use_multipath: True
+
 Client role
 -----------