Fixed devnull redirects to work on all python3 versions. subprocess.DEVNULL was not defined in Python 3.2, causing script failure on Precise
pep8 cleanup as much as I could (remaining lines are all output lines)
"automatic merge of lp:~bladernr/checkbox/1399481-fix-network-script-devnull-calls/ by tarmac [r=zkrynicki][bug=1399481][author=bladernr]"