Fix validateBonding tests without bonding

There were remnants of the old validateBonding test
that were made obsolete by:
    Change-Id: I023a5bb8a52719559bb9d4716f25e0cba8b3530b
That monkeypatching is not needed anymore. Now we just skip
the test if bonding is not loaded, i.e., BONDING_MASTERS
sysfs does not exist.

Change-Id: Idf461f1fbca682c44cae564cb32e4b7973c1f000
Signed-off-by: Antoni S. Puimedon <asegurap@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/12981
Reviewed-by: Dan Kenigsberg <danken@redhat.com>
Tested-by: Dan Kenigsberg <danken@redhat.com>