New 'network-bridge' script that uses ifdown/ifup to configure the interface rather...

New 'network-bridge' script that uses ifdown/ifup to configure the interface rather than trying to transfer addresses and routes. (Suggested by Gerd Knorr)

Although Li Ge has had problems with this script he had trouble with the previous too. I think this new one should work for more people, particularly those using DHCP on their primary dom0 interface.

Debugging is currently enabled ("sh -x") so a log of the script's execution is output to /var/log/xend.log

Signed-off-by: ian@xensource.com
--HG--
rename : tools/examples/network => tools/examples/network-bridge