Fix to clean up others sockets if the shell server

xterm/index.cgi

@@ -254,5 +254,3 @@ else {
 	}
 print "</script>\n";
 &ui_print_footer();
-
-&cleanup_old_websockets([$port]);

xterm/shellserver.pl

@@ -166,3 +166,4 @@ Net::WebSocket::Server->new(
 )->start;
 print STDERR "exited websockets server\n";
 &cleanup_miniserv($port);
+&cleanup_old_websockets([$port]);