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>

t/t0001-init.sh

@@ -12,8 +12,8 @@ check_config () {
 		echo "expected a directory $1, a file $1/config and $1/refs"
 		return 1
 	fi
-	bare=$(GIT_CONFIG="$1/config" git config --bool core.bare)
-	worktree=$(GIT_CONFIG="$1/config" git config core.worktree) ||
+	bare=$(cd "$1" && git config --bool core.bare)
+	worktree=$(cd "$1" && git config core.worktree) ||
 	worktree=unset
 
 	test "$bare" = "$2" && test "$worktree" = "$3" || {

t/t5701-clone-local.sh

@@ -12,8 +12,8 @@ test_expect_success 'preparing origin repository' '
 	: >file && git add . && git commit -m1 &&
 	git clone --bare . a.git &&
 	git clone --bare . x &&
-	test "$(GIT_CONFIG=a.git/config git config --bool core.bare)" = true &&
-	test "$(GIT_CONFIG=x/config git config --bool core.bare)" = true &&
+	test "$(cd a.git && git config --bool core.bare)" = true &&
+	test "$(cd x && git config --bool core.bare)" = true &&
 	git bundle create b1.bundle --all &&
 	git bundle create b2.bundle master &&
 	mkdir dir &&
@@ -24,7 +24,7 @@ test_expect_success 'preparing origin repository' '
 test_expect_success 'local clone without .git suffix' '
 	git clone -l -s a b &&
 	(cd b &&
-	test "$(GIT_CONFIG=.git/config git config --bool core.bare)" = false &&
+	test "$(git config --bool core.bare)" = false &&
 	git fetch)
 '