link monitor: Reuse Link parsing

'ip -d -o link show' and 'ip monitor link' lines share most of the
format. The main difference is that the latter has the special
deleted lines.

This patch makes the monitor parser worry only about the specific
monitor bits ('deleted') and reuse the logic iproute2 link entry
parsing.

Change-Id: I347939595ca32648e53ec4fbf5eb900dcbe5c050
Signed-off-by: Antoni S. Puimedon <asegurap@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/22079
Reviewed-by: Dan Kenigsberg <danken@redhat.com>