Use `static-network-up` instead of `stopped networking` in upstart script

This works on ubuntu oneiric (11.10) and above, and fixes the behaviour for
ubuntu quantal (12.10) and above which no longer fire `stopped networking`
during startup.

Upstart cookbook bug describing the issue:
https://bugs.launchpad.net/upstart-cookbook/+bug/1222004
Merge branch 'use-static-network-up'