Update metainfo install path

[tobbez]

The metainfo file was being installed into /usr/share/appdata, but that path has been deprecated. Metainfo files should instead be installed into /usr/share/metainfo.

Closes: https://dev.deluge-torrent.org/ticket/3394 Ref: https://www.freedesktop.org/software/appstream/docs/chap-Metadata.html#sect-Metadata-GenericComponent

[cas--]

Should appdata also be renamed to metainfo?

[tobbez]

If you're asking about the file name in the install path, then no. The file should still be named %{id}.metainfo.xml.

On the other hand, if you're asking about the variable names in setup.py and the path within the repository, then that's up to you. I can update the PR to change those too if you prefer.

[cas--]

Apologies for the unclear question. This commit only changes the directory where the files should be located but the files themselves should also be renamed:

appdata_data = 'deluge/ui/data/share/appdata/deluge.appdata.xml'

For consistency all references to appdata should be replaced with metainfo, so all variables, dirs and files.

[tobbez]

Updated.

There are now no remaining appdata references.