RFR: 8153044: Allow a property to control location of tzdb.dat file

[mark.reinhold at oracle.com]

2016/7/7 8:02:21 -0700, scolebourne at joda.org:
> I won't block this change, but I remain unenthused. There are other
> ways to control the time-zone data, and since tzdb.dat is currently a
> private format file that is part of the internals of the JDK, it seems
> odd to be exposing it.

I agree.  This is an internal implementation detail.  If we define this
system property then it becomes something we'll have to document and
support, likely for a very long time.  I suggest WNF.

> Having the tzdb.dat as a versioned module that could be replaced, or
> linked in would, by contrast, be potentially very useful.

Hrm, now if we only had a module system ...

- Mark