[tz] Print zdump and zic program names in --version output

[Robert Elz]

    Date:        Fri, 9 Nov 2012 21:47:54 +0000 (UTC)
    From:        "Joseph S. Myers" <jsm at polyomino.org.uk>
    Message-ID:  <Pine.LNX.4.64.1211092145080.25519 at digraph.polyomino.org.uk>

  | in accordance with the GNU standards for what --version should print.

I don't actually care what --version prints (though keeping it relatively
constant - other than its value of course - over time, so any scripts that
parse it don't have to keep being updated is a good idea).

But why do we care about GNU standards?   Sure, POSIX, and IEEE C make
sense to follow, but GNU??   Why??

kre