Pin python-pymysql latest version MOS repo.

Change-Id: Ia42b38284331484df7bafe80773b7f5e1b28fd01
diff --git a/neutron/compute/cluster.yml b/neutron/compute/cluster.yml
index d6674f0..fc87e84 100644
--- a/neutron/compute/cluster.yml
+++ b/neutron/compute/cluster.yml
@@ -3,6 +3,12 @@
 parameters:
   _param:
     neutron_enable_qos: False
+  linux:
+    system:
+      package:
+        python-pymysql:
+          fromrepo: ${_param:openstack_version}
+          version: latest
   neutron:
     compute:
       dvr: ${_param:neutron_compute_dvr}