ipwrapper: Move hidden bonds' nic logic from netinfo

This patch moves the remaining logic of what could hide a nic to
ipwrapper so that it is all well enclosed in a single digestible
method.

Since the nic master is retrieved from the ip links, that needs
a couple of tweaks in netinfoTests, namely:
- Adding the master information to the link line for the nics to
  be hidden. Which means that the tmpdir fixture is not necessary
  anymore.
- Monkeypatch the new Link info about existing bonds and the
  hidden config.

Change-Id: I5a49d7da35f8453b7297b0599db232867a4b1078
Signed-off-by: Antoni S. Puimedon <asegurap@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/21561
Reviewed-by: Dan Kenigsberg <danken@redhat.com>