t: stop using GIT_CONFIG to cross repo boundaries
Some tests want to check or set config in another
repository. E.g., t1000 creates repositories and makes sure
that their core.bare and core.worktree settings are what we
expect. We can do this with:
GIT_CONFIG=$repo/.git/config git config ...
but it better shows the intent to just enter the repository
and let "git config" do the normal lookups:
(cd $repo && git config ...)
In theory, this would cause us to use an extra subshell, but
in all such cases, we are actually already in a subshell.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>