netinfo: use link objects for getting known information

The link objects always contain certain information that used to be
retrieved separately. This patch avoids this extra info fetching.

Change-Id: I2f1235f4a565084d9cf0247ac81d189afb2efac5
Signed-off-by: Antoni S. Puimedon <asegurap@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/23291
Reviewed-by: Dan Kenigsberg <danken@redhat.com>