Remove a crash where ScriptManager was deinitialized wrongly

src/engine/openspaceengine.cpp

@@ -208,7 +208,6 @@ bool OpenSpaceEngine::create(int argc, char** argv,
 }
 
 void OpenSpaceEngine::destroy() {
-
 	delete _engine;
 	ghoul::systemcapabilities::SystemCapabilities::deinitialize();
 	FactoryManager::deinitialize();

src/scripting/scriptengine.cpp

@@ -209,8 +209,10 @@ bool ScriptEngine::initialize() {
 }
 
 void ScriptEngine::deinitialize() {
-    lua_close(_state);
-    _state = nullptr;
+    if (_state) {
+        lua_close(_state);
+        _state = nullptr;
+    }
 }
 
 void ScriptEngine::addLibrary(LuaLibrary library) {