ipv4: Don't add TCP-code in inet_sock_destruct

[Note from Zheng Liu]
This patch fixes a bug that meets in our product system in alipay.

Reference: bb68b64724a4fd6b93d83b39aeffa4aadb2562fc
Patch-mainline: v3.6-rc5-987-gbb68b64
Signed-off-by: Christoph Paasch <christoph.paasch@uclouvain.be>
Acked-by: H.K. Jerry Chu <hkchu@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>