pick up Translation-* even if only compressed available

pick up Translation-* even if only compressed available

On CD-ROMs Translation-* files are only in compressed form included in
the Release file. This used to work while we had no record of
Translation-* files in the Release file at all as APT would have just
guessed the (compressed) filename and accepted it (unchecked), but now
that it checks for the presents of entries and if it finds records it
expects the uncompressed to be verifiable.

This commit relaxes this requirement again to fix the regression.
We are still secure "enough" as we can validate the compressed file we have
downloaded, so we don't loose anything by not requiring a hashsum for
the uncompressed files to double-check them.

Closes: 717665