Changes to make devstack work with the essex + xen

Change-Id: If932d82ec72494d871ad65ae863947816e719624
diff --git a/tools/xen/build_domU.sh b/tools/xen/build_domU.sh
index d79d5c3..642b40f 100755
--- a/tools/xen/build_domU.sh
+++ b/tools/xen/build_domU.sh
@@ -33,12 +33,12 @@
 
 # VM network params
 VM_NETMASK=${VM_NETMASK:-255.255.255.0}
-VM_BR=${VM_BR:-xenbr1}
+VM_BR=${VM_BR:-xapi1}
 VM_VLAN=${VM_VLAN:-100}
 
 # MGMT network params
 MGT_NETMASK=${MGT_NETMASK:-255.255.255.0}
-MGT_BR=${MGT_BR:-xenbr2}
+MGT_BR=${MGT_BR:-xapi2}
 MGT_VLAN=${MGT_VLAN:-101}
 
 # VM Password
@@ -205,8 +205,9 @@
 
 # Checkout nova
 if [ ! -d $TOP_DIR/nova ]; then
-    git clone git://github.com/cloudbuilders/nova.git
-    git checkout diablo
+    git clone $NOVA_REPO
+    cd $TOP_DIR/nova
+    git checkout $NOVA_BRANCH
 fi 
 
 # Run devstack on launch