Merge branch 'ob/core-attributesfile-in-repository' into seen

The core.attributesfile is intended to be set per repository, but
were kept track of by a single global variable in-core, which has
been corrected by moving it to per-repository data structure.

Comments?

* ob/core-attributesfile-in-repository:
  environment: move "core.attributesFile" into repo-setting

diff --cc environment.c
Simple merge

diff --cc environment.h
Simple merge