So on android we see that the packets are being forwarded through
the vpn tunnel, instead they are being forwarded out the normal
interface, so tcpdump on the host sees (hostip: tunneldst) which
cannot be forwarded in the local network.

The tunneldst, needs to be encapsulated by the vpn and send on the
underlay.  But that is not happening, on linux it happens,
presumably, linux routing sees the route and correctly forwards,
not the case for android which sends it over the wifi/cell network
as is.

Signed-off-by: Lincoln Thurlow <lincoln@isi.edu>