consistently use Py_TYPE, Py_REFCNT, and correct initializer macros (#3563)

This no-op change makes 2.7 more consistent with 3.x to ease comparison and backports.
diff --git a/Objects/fileobject.c b/Objects/fileobject.c
index a7d64ba..7e07a53 100644
--- a/Objects/fileobject.c
+++ b/Objects/fileobject.c
@@ -427,7 +427,7 @@
     if (local_fp != NULL) {
         local_close = f->f_close;
         if (local_close != NULL && f->unlocked_count > 0) {
-            if (f->ob_refcnt > 0) {
+            if (Py_REFCNT(f) > 0) {
                 PyErr_SetString(PyExc_IOError,
                     "close() called during concurrent "
                     "operation on the same file object.");