Previously, the mesh was running whenever the appropriate hardware
and firmware was present.

Now we only run the mesh when the interface is running.

Also simplifies interface management a little.
Signed-off-by: NDaniel Drake <dsd@laptop.org>
Acked-by: NDan Williams <dcbw@redhat.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>