Martin von Zweigbergk <martinvonz@google.com> [Thu, 15 Jun 2017 15:13:18 -0700] rev 32889
localrepo: remove unused addchangegroup() (API)
This completes the cleanup started in d3775db748a0 (localrepo: move
the addchangegroup method in changegroup module, 2014-04-01).