[tz] tzdata2016g missing version information

[Alexander Belopolsky]

> On Sep 29, 2016, at 5:47 PM, Paul Eggert <eggert at cs.ucla.edu> wrote:
> 
> There are two disadvantages of that. First, the version string might happen to look like the start of a tz binary file (admittedly unlikely). Second and more important, this is a metadata file and there are likely to be future extensions (e.g., to specify the range of supported time stamps), so an extensible format is called for.

Maybe zic could put the version string in every zoneinfo file. There is plenty of reserved space in the current format to hold 5-6 characters.