Code review comment for lp:~jtv/maas/bug-1373103

Okay, I understand it is quite urgent to fix this so I'm approving this MP.

It's probably worth adding a little note to state that this is a temporary fix because it's really ugly as it stands.

Not trying to configure the interfaces if the file is not present might be a better fix.

In any case, if it wasn't temporary, this code would really belong to the OS code.