BZ #1162794: Properly configure bond interfaces with vlans

https://bugzilla.redhat.com/show_bug.cgi?id=1162794

If no MAC address was associated with a VLAN's parent interface (as is
the case of bonds), the interface would not be properly set up.
Merge pull request #111 from bcrochet/bz/1162794

BZ #1162794: Properly configure bond interfaces with vlans