tools/hotplug, Use udev rules instead of qemu script to setup the bridge.

tools/hotplug, Use udev rules instead of qemu script to setup the bridge.
From: Anthony PERARD <anthony.perard@citrix.com>

This patch adds a second argument to vif-bridge script. It can be "vif"
or "tap". "vif" give the default behavior and "tap" just add the
interface to the found bridge when the action is "add".

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
 tools/hotplug/Linux/vif-bridge        |   20 ++++++---
 tools/hotplug/Linux/vif-common.sh     |   70 ++++++++++++++++++++++++---------
 tools/hotplug/Linux/xen-backend.rules |    5 +-
 tools/libxl/libxl.c                   |    6 +-
 4 files changed, 70 insertions(+), 31 deletions(-)