Ensure Open vSwitch can be installed on RHEL6.

 * RHEL6 does not include Open vSwitch in the default repos, but it
   is available via the RDO repo.  This patch automatically
   configures the RDO repo for RHEL6.
 * The openvswitch package is now listed as an rpm dependency to
   ensure it can be cached by a pre-built CI environment.

Change-Id: I8f93f53039cca4ff29bcb91720be7bb047b3ed8a
diff --git a/files/rpms/quantum b/files/rpms/quantum
index 32c6f62..8827d5a 100644
--- a/files/rpms/quantum
+++ b/files/rpms/quantum
@@ -4,6 +4,7 @@
 iptables
 iputils
 mysql-server # NOPRIME
+openvswitch # NOPRIME
 python-boto
 python-eventlet
 python-greenlet