Watch for neutron.conf in neutron_dvr_agents state

L3 and metadata agent get their config from neutron.conf as well
as from l3_agent.ini and metadata_agent.ini correspondingly.
That's why we need to watch for changes in neutron.conf too.

Change-Id: Ie30b2c2128bfbb50a87c55c3ee9b21111096919e
diff --git a/neutron/compute.sls b/neutron/compute.sls
index cb02136..9770b85 100644
--- a/neutron/compute.sls
+++ b/neutron/compute.sls
@@ -59,6 +59,7 @@
       - neutron-l3-agent
       - neutron-metadata-agent
     - watch:
+      - file: /etc/neutron/neutron.conf
       - file: /etc/neutron/l3_agent.ini
       - file: /etc/neutron/metadata_agent.ini
     - require: