Scripts/Commands: Fix memory leak in ".gobject add" command

Valgrind log:
 158 (104 direct, 54 indirect) bytes in 1 blocks are definitely lost in loss record 24 of 73
 at operator new(unsigned long) (vg_replace_malloc.c:319)
 by GameObjectModel::Create(GameObject const&) (GameObjectModel.cpp:152)
 by GameObject::Create(unsigned int, unsigned int, Map*, unsigned int, float, float, float, float, float, float, float, float, unsigned int, GOState, unsigned int) (GameObject.cpp:237)
 by gobject_commandscript::HandleGameObjectAddCommand(ChatHandler*, char const*) (cs_gobject.cpp:155)