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/floatobject.c b/Objects/floatobject.c
index 801f286..360ef94 100644
--- a/Objects/floatobject.c
+++ b/Objects/floatobject.c
@@ -65,7 +65,7 @@
     return DBL_MIN;
 }
 
-static PyTypeObject FloatInfoType = {0, 0, 0, 0, 0, 0};
+static PyTypeObject FloatInfoType;
 
 PyDoc_STRVAR(floatinfo__doc__,
 "sys.float_info\n\