[packagekit] backend authors: get-description has changed

[James Bowes]

Hi all:

A while ago we added get-files and changed get-description to not send
a package's file list over dbus. Tonight I finished removing the
filelist logic from get-description. Since backends would have been
broken if I didn't touch them, I figured there was nothing to lose in
trying to update all the backends myself (given that the change was
usually a single line). Please do check commit
3f71413eff5dda125444da3992bf2884e02baada and make sure I haven't
broken anything.

Thanks,
-James