netinfo: drop unused NetInfo.getBridgelessNetworkForIface

Commit fb443166d483dbff199f7e35313304f849b98470 not only changed the
method so that it would return only a single network, but also
removed its only usage. It is time to drop it.

Change-Id: Ic0287b2a899dbb5c3568851172da9415963c3324
Signed-off-by: Antoni S. Puimedon <asegurap@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/29603
Reviewed-by: Dan Kenigsberg <danken@redhat.com>