ofproto-dpif-xlate: Fix in_port=controller case for NORMAL action

The problem mentioned by Simon Horman in the following mail.
http://openvswitch.org/pipermail/dev/2014-April/039492.html

Cc: Simon Horman <horms@verge.net.au>
Acked-by: Ben Pfaff <blp@nicira.com>
Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
datapath: clear l4_rxhash in skb_clear_hash.

Signed-off-by: Pritesh Kothari <pritesh.kothari@cisco.com>
Signed-off-by: Jesse Gross <jesse@nicira.com>