gitweb: supply '-n' to gzip for identical output

For projects that do not release official archives, gitweb's snapshot feature would be an excellent alternative, and but without the '-n' ('--no-name') argument, gzip includes a timestamp in output which results in different files. Because some systems hash/checksum downloaded files to ensure integrity of the tarball (e.g FreeBSD), it is desirable to produce tarballs in a reproducible way for that purpose. Whilst '--no-name' is more descriptive, the long version of the flag is not supported on all systems. In particular, OpenBSD does not appear to support it. Supply '-n' to gzip to exclude timestamp from output and produce idential output every time. Signed-off-by: Fraser Tweedale <frase@frase.id.au> Acked-by: Jakub Narebski <jnareb@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>