Fix building on Windows PYTHON-414

Author: behackett

pymongo/_cmessagemodule.c

@@ -709,8 +709,9 @@ static PyObject* _cbson_do_batched_insert(PyObject* self, PyObject* args) {
  if (!PyObject_CallMethod(client,
  "_send_message", "NO", result, send_gle)) {
  PyObject *etype = NULL, *evalue = NULL, *etrace = NULL;
+ PyObject* OperationFailure;
  PyErr_Fetch(&etype, &evalue, &etrace);
- PyObject* OperationFailure = _error("OperationFailure");
+ OperationFailure = _error("OperationFailure");
  if (OperationFailure) {
  if (PyErr_GivenExceptionMatches(etype, OperationFailure)) {
  if (!safe || continue_on_error) {