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/tools/xen/xenrc b/tools/xen/xenrc
index 7aaafd2..0ed3a6a 100644
--- a/tools/xen/xenrc
+++ b/tools/xen/xenrc
@@ -25,6 +25,7 @@
 MGT_BRIDGE_OR_NET_NAME="xenbr0"
 VM_BRIDGE_OR_NET_NAME="OpenStack VM Network"
 PUB_BRIDGE_OR_NET_NAME="OpenStack Public Network"
+XEN_INT_BRIDGE_OR_NET_NAME="OpenStack VM Integration Network"
 
 # VM Password
 GUEST_PASSWORD=${GUEST_PASSWORD:-secrete}