RFR : 8180946: Use Mercurial tags to identify GA builds

[mark.reinhold at oracle.com]

2018/10/31 1:58:05 -0700, sean.coffey at oracle.com:
> Thanks for the review Magnus.
> 
> cc'ing ops team. Is it possible to get this patch sponsored and 
> installed on the mercurial servers ?

Done.

- Mark