[SCTP]: Fix assertion (!atomic_read(&sk->sk_rmem_alloc)) failed message

In current implementation, LKSCTP does receive buffer accounting for
data in sctp_receive_queue and pd_lobby. However, LKSCTP don't do
accounting for data in frag_list when data is fragmented. In addition,
LKSCTP doesn't do accounting for data in reasm and lobby queue in
structure sctp_ulpq.
When there are date in these queue, assertion failed message is printed
in inet_sock_destruct because sk_rmem_alloc of oldsk does not become 0
when socket is destroyed.

Signed-off-by: Tsutomu Fujii <t-fujii@nb.jp.nec.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
SCTP_STATIC void sctp_shutdown(struct sock *sk, int how)
{
	struct sctp_endpoint *ep;
	struct sctp_association *asoc;

	if (!sctp_style(sk, TCP))
		return;

	if (how & SEND_SHUTDOWN) {
		ep = sctp_sk(sk)->ep;
		if (!list_empty(&ep->asocs)) {
			asoc = list_entry(ep->asocs.next,
					  struct sctp_association, asocs);
			sctp_primitive_SHUTDOWN(asoc, NULL);
		}
	}
}

SCTP_STATIC void sctp_shutdown(struct sock *sk, int how)
{
	struct sctp_endpoint *ep;
	struct sctp_association *asoc;

	if (!sctp_style(sk, TCP))
		return;

	if (how & SEND_SHUTDOWN) {
		ep = sctp_sk(sk)->ep;
		if (!list_empty(&ep->asocs)) {
			asoc = list_entry(ep->asocs.next,
					  struct sctp_association, asocs);
			sctp_primitive_SHUTDOWN(asoc, NULL);
		}
	}
}
