ejabberd_listener: Let supervisor terminate child

If a TCP connection was closed before the socket was handed over to a
supervised child process, let the supervisor terminate the process
rather than killing it directly.  This avoids crash log entries
generated by the supervisor.

src/ejabberd_listener.erl

@@ -307,7 +307,12 @@ start_connection(Module, Arity, Socket, State, Sup) ->
 		    Module:accept(Pid),
 		    {ok, Pid};
 		Err ->
-		    exit(Pid, kill),
+		    case Sup of
+			undefined ->
+			    exit(Pid, kill);
+			_ ->
+			    supervisor:terminate_child(Sup, Pid)
+		    end,
 		    Err
 	    end;
 	Err ->