[TCP]: Restore SKB socket owner setting in tcp_transmit_skb().

[TCP]: Restore SKB socket owner setting in tcp_transmit_skb().

Revert 8b454b611f68f1671cc64405ad1b5305dca12f89

We can't elide the skb_set_owner_w() here because things like certain
netfilter targets (such as owner MATCH) need a socket to be set on the
SKB for correct operation.

Thanks to Jan Engelhardt and other netfilter list members for
pointing this out.

Signed-off-by: David S. Miller <davem@davemloft.net>