Git commits in Moodle 1.9.7 by Jenny Gray

commit 7bfea4b502e5ef17817fb50c97ffa60bd57e5cdc
Author: Jenny Gray <j.m.gray@open.ac.uk>
Date:   Wed, 04 Nov 2009 20:16:18 +0800
Tag:    v1.9.7

MDL-20665 fixed error from postgres on validating duplicate category name when entering new category