xenapi: Cleanup networking

OpenStack VM had 4 interfaces, from which eth0 was connected to HIMN (Host
Internal Management Network), and not used at all. The reason for not
using this interface according to johngarbutt is:
 - VNC console would not work
 - migrations would not work
 - many other things
This change removes the interface, thus devstack is providing the
same architecture as described in the official documentation, YAGNI
applied on the HIMN:

    http://goo.gl/dmrNF

The change also modifies some defaults, so it's easier to get started:
 - The Ubuntu VM is network-installed through the management network
 - OS VM is getting its address on the management network through DHCP
 - Default Public IP addresses aligned to stack.sh defaults
 - OS Services are listening on Management Interface

Related to blueprint xenapi-devstack-cleanup

Change-Id: I73c9751ade6f4786b8b682a1994cb87f0a624379
diff --git a/tools/xen/functions b/tools/xen/functions
index ebfd483..f22a561 100644
--- a/tools/xen/functions
+++ b/tools/xen/functions
@@ -224,3 +224,19 @@
     pv_args=$(xe vm-param-get param-name=PV-args uuid=$vm)
     xe vm-param-set PV-args="$pv_args $kernel_args" uuid=$vm
 }
+
+function destroy_all_vifs_of()
+{
+    local vm_name_label
+
+    vm_name_label="$1"
+
+    local vm
+
+    vm=$(_vm_uuid "$vm_name_label")
+    IFS=,
+    for vif in $(xe vif-list vm-uuid=$vm --minimal); do
+        xe vif-destroy uuid="$vif"
+    done
+    unset IFS
+}