[3.14] Fix unlikely potential reference leak in _locale._getdefaultlocale (GH-145250) (GH-145302)

It occurs in a code which perhaps never executed.
(cherry picked from commit 6ea84b2726)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

Modules/_localemodule.c

@@ -579,7 +579,6 @@ _locale__getdefaultlocale_impl(PyObject *module)
     }
 
     /* cannot determine the language code (very unlikely) */
-    Py_INCREF(Py_None);
     return Py_BuildValue("Os", Py_None, encoding);
 }
 #endif