xenapi - quantum: L2 agents for dom0 and domU

This patch makes it easier to support the all-in-one installation of
XenServer with Quantum:
- separate agents for domU and dom0 openvswitches. The domU agent's name
  is "q-domua", and the dom0 agent is called "q-agt"
- create a physnet1 physical network to connect those openvswitches

Note: This patch depends on the quantum patch:

    https://review.openstack.org/15022

For a diagram, see:
    http://goo.gl/BuAdg

Change-Id: Iff851438553528b9051edd380ecbb2c0415cbf78
diff --git a/lib/quantum b/lib/quantum
index c36a743..d85c648 100644
--- a/lib/quantum
+++ b/lib/quantum
@@ -386,6 +386,11 @@
     screen_it q-l3 "cd $QUANTUM_DIR && python $AGENT_L3_BINARY --config-file $QUANTUM_CONF --config-file=$Q_L3_CONF_FILE"
     screen_it q-meta "cd $QUANTUM_DIR && python $AGENT_META_BINARY --config-file $QUANTUM_CONF --config-file=$Q_META_CONF_FILE"
 
+    if [ "$VIRT_DRIVER" = 'xenserver' ]; then
+        # For XenServer, start an agent for the domU openvswitch
+        screen_it q-domua "cd $QUANTUM_DIR && python $AGENT_BINARY --config-file $QUANTUM_CONF --config-file /$Q_PLUGIN_CONF_FILE.domU"
+    fi
+
     if is_service_enabled q-lbaas; then
         screen_it q-lbaas "cd $QUANTUM_DIR && python $AGENT_LBAAS_BINARY --config-file $QUANTUM_CONF --config-file=$LBAAS_AGENT_CONF_FILENAME"
     fi