netinfo updating infra for functional tests

This patch adds a way to implicitly have current network information
in the functional tests when performing operations that alter the
networking state.

Change-Id: I232534910017a8062b39f22f6df8d2fc2c119e0a
Signed-off-by: Antoni S. Puimedon <asegurap@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/16656
Reviewed-by: Mark Wu <wudxw@linux.vnet.ibm.com>
Tested-by: Mark Wu <wudxw@linux.vnet.ibm.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>