Simplification of CategoryAdd.

git-svn-id: https://svn.apache.org/repos/asf/roller/trunk@1570824 13f79535-47bb-0310-9956-ffa450edef68
Simplification of CategoryAdd, part #2.

git-svn-id: https://svn.apache.org/repos/asf/roller/trunk@1570825 13f79535-47bb-0310-9956-ffa450edef68