After updating desktop database, menu entry without categories= in .desktop file disappears from application menu.

the sqliteman provides such as (category less) .desktop file. it's normally shown under 'Other' menu directory.

Steps to Reproduce:
1. start xfce4.
2. install or uninstall desktop apps which provides menu entry to update desktop database.
3. update desktop database by `update-desktop-database'.

Version: git-master

Build & Platform:
Build 2014-03-01 on ArchLinux