Since the bonds interface changed to a lot more possible values we create a
mapping of kernel bond attribute names and values to networkd attributes.
Those match for the most part, but have to transformed slightly.
There is also an assert that unknown options won’t slip through silently.
Regression introduced by 0cb487ee04.
This changed the result for defaultGateway to be a submodule instead of
just a plain string, so instead of using just cfg.defaultGateway we need
to pass cfg.defaultGateway.address now.
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
Cc: @abbradar