DejaDup AppData file

[Richard Hughes <hughsient gmail com>]

Hi,

Thanks for writing the AppData file for DejaDup -- one small problem:
https://github.com/hughsie/createrepo_as_logs/blob/master/deja-dup.log

This means there's no one-line short summary available for the
application -- this is usually taken from the "Comment=" line in the
desktop file, but it appears deja-dup.desktop doesn't have one. This
is required for the AppStream specification and used in gnome-software
and apper.

Could you either add a one line <summary> in the AppData or add a
Comment in the desktop file please? Thanks, and sorry for the bother!

Richard.