Fix minor network functional tests issues

Some tests were asserting that networks existed based on out
of date statuses.

Change-Id: I5a029f6da66f59b2e0394d3f4bb26637aa0b59c6
Signed-off-by: Assaf Muller <amuller@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/20859
Reviewed-by: Antoni Segura Puimedon <asegurap@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>