Bugfix

Bugfix:
/root/entity/Entity/fleet.js:222
scope.perlevel[data.quitlevel].substract(1);
^TypeError: Cannot call method 'substract' of undefined    at
Object.server.simpleserver.onReceive
(/root/entity/Entity/fleet.js:222:38)    at simpleserver.onReceive
(/root/entity/Entity/simpleserver.js:78:15)    at WebSocket.<anonymous>
(/root/entity/Entity/simpleserver.js:34:10)    at
WebSocket.EventEmitter.emit (events.js:98:17)    at
Receiver.self._receiver.ontext
(/root/entity/Entity/node_modules/ws/lib/WebSocket.js:544:10)    at
Receiver.opcodes.1.finish
(/root/entity/Entity/node_modules/ws/lib/Receiver.js:397:14)    at
Receiver.expectHandler
(/root/entity/Entity/node_modules/ws/lib/Receiver.js:378:33)    at
Receiver.add
(/root/entity/Entity/node_modules/ws/lib/Receiver.js:93:24)    at
Socket.firstHandler
(/root/entity/Entity/node_modules/ws/lib/WebSocket.js:524:22)    at
Socket.EventEmitter.emit (events.js:95:17)