client: If we have a pre-connected FD, set state to SOCKET_CONNECTED
client: If we have a pre-connected FD, set state to SOCKET_CONNECTED

Otherwise applications providing their own fd end up tripping an
assertion, since the session is just in _CONNECTING.

Reviewed-by: Andreas Schneider <5be00ddc76278cf6077f5047ca3384a88460c671@cryptomilk.org>

mwgoldsmith/ssh,mwgoldsmith/ssh,mwgoldsmith/ssh,mwgoldsmith/libssh,mwgoldsmith/ssh,mwgoldsmith/libssh,mwgoldsmith/libssh,mwgoldsmith/libssh