Fix misuse of Py_INCREF in module creation.

Differential Revision: https://developer.blender.org/D3697

source/blender/python/generic/idprop_py_api.c

@@ -1811,7 +1811,6 @@ PyObject *BPyInit_idprop(void)
 	/* idprop.types */
 	PyModule_AddObject(mod, "types", (submodule = BPyInit_idprop_types()));
 	PyDict_SetItem(sys_modules, PyModule_GetNameObject(submodule), submodule);
-	Py_INCREF(submodule);
 
 	return mod;
 }