Fixed #22551 -- Made oracle backend method Python 3 compatible

Thanks fatal10110 at gmail.com for the report. The fix is 1.6-only
because that code has been refactored in 1.7 (6983201c).
'Docs-only' forward port of 120a9812 from 1.6.x.

docs/releases/1.6.5.txt

@@ -9,4 +9,5 @@ Django 1.6.5 fixes several bugs in 1.6.4.
 Bugfixes
 ========
 
-* ...
+* Made the ``year_lookup_bounds_for_datetime_field`` Oracle backend method
+  Python 3 compatible (`#22551 <http://code.djangoproject.com/ticket/22551>`_).