Mark netinfoTests.testGetIfaceByIP as a broken test

The test has been failing since python-ethtool-0.6-5.

The goal is to get rid of the function and its test, and
use a different approach to solve the problem that the function
was originally solving.

Change-Id: I4c30963f80bf13bc99a059232ec435c1672b2def
Signed-off-by: Assaf Muller <amuller@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/21471
Reviewed-by: Dan Kenigsberg <danken@redhat.com>
Tested-by: Dan Kenigsberg <danken@redhat.com>