Fix a small bug in the tcp_log_id where the bucket

was unlocked and yet the bucket-unlock flag was not
changed to false. This can cause a panic if INVARIANTS
is on and we go through the right path (though rare).

Reported by:	syzbot+179a1ad49f3c4c215fa2@syzkaller.appspotmail.com
Reviewed by:	tuexen@
MFC after:	1 week

sys/netinet/tcp_output.c

@@ -138,7 +138,8 @@ SYSCTL_INT(_net_inet_tcp, OID_AUTO, sendbuf_auto_lowat, CTLFLAG_VNET | CTLFLAG_R
  * non-ACK.
  */
 #define TCP_XMIT_TIMER_ASSERT(tp, len, th_flags)			\
-	KASSERT(((len) == 0 && ((th_flags) & (TH_SYN | TH_FIN)) == 0) ||\
+	KASSERT(((len) == 0 && ((th_flags) &				\
+				(TH_SYN | TH_FIN | TH_RST)) != 0) ||	\
 	    tcp_timer_active((tp), TT_REXMT) ||				\
 	    tcp_timer_active((tp), TT_PERSIST),				\
 	    ("neither rexmt nor persist timer is set"))