FCmdrYumBackend: Only delete our own .repo files.

Whoa, glad that one didn't get loose!  Only damaged my system.
Add fcmdr_recursive_delete_sync().

Deletes directories by recursively deleting its contents.

Copied from e_file_recursive_delete_sync() in libedataserver.
FCmdrGSettingsBackend: Delete old dconf databases.

Recursively delete "/etc/dconf/db/fleet-commander-$UID.d/" if $UID does
not appear in the list of profiles to apply.