xenapi: xe network-attach for OVS bridge creation

For Neutron we need an additional OVS bridge to be present. The xe
network-create command did not create the bridge immediately. A
workaround was applied to attach a network interface to that network,
forcing xapi to create the underlying OVS bridge. It turned out, that
the xe network-attach command could be used instead, so the workaround
is removed and replaced with the proper solution by this patch.

Fixes bug 1197305

Change-Id: I10cc763531b71238f0bc12a12de985f8f35d7e27
diff --git a/tools/xen/install_os_domU.sh b/tools/xen/install_os_domU.sh
index 21aa729..6eb3013 100755
--- a/tools/xen/install_os_domU.sh
+++ b/tools/xen/install_os_domU.sh
@@ -50,6 +50,15 @@
 
 cd $THIS_DIR
 
+# Die if multiple hosts listed
+if have_multiple_hosts; then
+    cat >&2 << EOF
+ERROR: multiple hosts found. This might mean that the XenServer is a member
+of a pool - Exiting.
+EOF
+    exit 1
+fi
+
 # Install plugins
 
 ## Nova plugins
@@ -256,7 +265,7 @@
 # is created by XenServer). This is required for Neutron. Also pass that as a
 # kernel parameter for DomU
 if is_service_enabled neutron; then
-    add_interface "$GUEST_NAME" "$XEN_INT_BRIDGE_OR_NET_NAME" $XEN_INT_DEV_NR
+    attach_network "$XEN_INT_BRIDGE_OR_NET_NAME"
 
     XEN_INTEGRATION_BRIDGE=$(bridge_for "$XEN_INT_BRIDGE_OR_NET_NAME")
     append_kernel_cmdline \