Pin python-pymysql latest version MOS repo.

Change-Id: Ia42b38284331484df7bafe80773b7f5e1b28fd01
diff --git a/designate/server/cluster.yml b/designate/server/cluster.yml
index 33eb632..eb6a5b6 100644
--- a/designate/server/cluster.yml
+++ b/designate/server/cluster.yml
@@ -4,6 +4,12 @@
 - system.haproxy.proxy.listen.openstack.designate
 - service.haproxy.proxy.single
 parameters:
+  linux:
+    system:
+      package:
+        python-pymysql:
+          fromrepo: ${_param:openstack_version}
+          version: latest
   designate:
     _support:
       sensu: