core/socket: close fds also on SOCKET_CLEAN state

Follow-up for c968d76a38

We'd only transition to SOCKET_CLEAN state if previously
inactive (see socket_clean()), hence no fds shall be persisted
in this state.

src/core/socket.c

@@ -1845,8 +1845,7 @@ static void socket_set_state(Socket *s, SocketState state) {
                     SOCKET_RUNNING,
                     SOCKET_STOP_PRE,
                     SOCKET_STOP_PRE_SIGTERM,
-                    SOCKET_STOP_PRE_SIGKILL,
-                    SOCKET_CLEANING))
+                    SOCKET_STOP_PRE_SIGKILL))
                 socket_close_fds(s);
 
         if (state != old_state)