Provide hashes for uncompressed Translation-* again

Implemented in 2f34797490 for bug #767253
released a few months later in v3.1.17, but then broken again a few days
later in 9dd0616b78 by removing the
uncompressed files too early.

tools/make_disc_trees.pl

@@ -601,7 +601,6 @@ sub recompress {
 	if ($filename =~ m/\/.*\/i18n\/(Translation.*)$/o &&
 		! ($filename =~ m/\/.*\/i18n\/(Translation.*gz)$/o)) {
 		system("gzip -9c < $_ >$_.gz");
-		unlink ($_);
 	}
 }