Extend OpenContrail salt-formula by disable_stats_collection option

Add support of disable_stats_collection configuration option for
vrouter agent to control statistics gathering (info about VMIs and VNs)
and reporting it to Analytics

Related-PROD: PROD-35795
Change-Id: I27051056911dd1215c2b46b6ee3ac320a3d80fa7
diff --git a/README.rst b/README.rst
index 02c4da6..128e69f 100644
--- a/README.rst
+++ b/README.rst
@@ -1636,6 +1636,23 @@
         flow_cache_timeout: 180
         ....
 
+Disable stats collection
+---------------------------------------------
+
+This option controlls gathering and sending statistics, related to VMIs
+and VNs, by vrouter agent to Analytics. If statistics should be gathered
+and sent - set this option to False. If statistics gathering should be
+disabled - set it to True.
+
+.. code-block:: yaml
+
+    opencontrail:
+      ....
+      compute
+        ....
+        disable_stats_collection: True
+        ....
+
 Usage
 =====