MT#4227 Move get_all_ifaces_for_host script to lib/

I suppose this was just misplaced by accident in:

| commit bf9515e9dcc0387c99c368592b22424179a4f5e1
| Author: Jon Bonilla <jbonilla@sipwise.com>
| Date:   Fri Sep 27 11:45:06 2013 +0200
|
|     Add helper script get_all_ifaces_for_host

Git-Dch: Ignore