[2.4/2.6] ip_nat_ftp - manip at the right place

	Hello,

	The attached patch changes the way the ip_nat_ftp helper
manipulates the packets:

- no manips => no fixup
- check the direction, do manip once and at the same time when the
headers are changed

	This is needed mostly for IPVS setups and I hope we do not
create troubles for other setups or FTP software.

	I'm not sure whether proper locking for 'info' is needed,
may be not. Tested for SNAT, DNAT, passive, active.

Regards

--
Julian Anastasov [off-list ref]