Add possibility to manage qemu security_driver

Related-Prod: PROD-35639
Change-Id: I87d8c44efddd95e19f7d10baa9d198caa77fbc07
diff --git a/README.rst b/README.rst
index 9acf16f..22f1189 100644
--- a/README.rst
+++ b/README.rst
@@ -1389,6 +1389,15 @@
         database:
           use_db_reconnect: true
 
+Set qemu security_driver
+========
+
+.. code-block:: yaml
+
+    nova:
+      compute:
+        security_driver: apparmor
+
 Upgrades
 ========