Fix defaultRoute handling

defaultRoute wasn't being past correctly to objectivizeNetwork,
so that defaultRoute was always None inside the function,
no matter what was past to it.

This meant that DEFROUTE=yes/no was never written to ifcfg files,
and 'ip route add default...' never applied by the iproute2
configurator.

Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1015009

Change-Id: I643c5fe9dab39833d73541b7a1bfaae9ae3e749d
Signed-off-by: Assaf Muller <amuller@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/24631
Reviewed-by: Antoni Segura Puimedon <asegurap@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>
Tested-by: Dan Kenigsberg <danken@redhat.com>