Another problem reported by Coverity. Backport candidate.

Objects/cellobject.c

@@ -8,6 +8,8 @@ PyCell_New(PyObject *obj)
 	PyCellObject *op;
 
 	op = (PyCellObject *)PyObject_GC_New(PyCellObject, &PyCell_Type);
+	if (op == NULL)
+		return NULL;
 	op->ob_ref = obj;
 	Py_XINCREF(obj);