This introduces a copy of amnesia.asc as tails.key and tails-i386-0.7.1.iso.asc
as tails-i386-0.7.1.iso.pgp.

Under Debian, those extensions are mapped to the mime Content-Types: pgp-keys
and pgp-signature respectively, allowing Apache servers to automatically adapt
the Content-Type header when sending those files.

The user will thus be prompted with an adapted default action while downloading
them: "Import Key" or "Verify Signature".

The original files could be removed.