Re: [PATCH 7/7] treewide: drop USE_THE_REPOSITORY_VARIABLE

Adapt a couple of trivial callers of `is_bare_repository()` to instead
use a repository available via the caller's context so that we can drop
the `USE_THE_REPOSITORY_VARIABLE` macro.

Signed-off-by: Patrick Steinhardt <redacted>
---
 builtin/repack.c        | 3 +--
 mailmap.c               | 6 ++----
 refs/reftable-backend.c | 4 +---
 setup.c                 | 3 +--
 4 files changed, 5 insertions(+), 11 deletions(-)

diff --git a/builtin/repack.c b/builtin/repack.c
index bbc6f51639..d0465fb4f5 100644
--- a/builtin/repack.c
+++ b/builtin/repack.c

@@ -1,4 +1,3 @@
-#define USE_THE_REPOSITORY_VARIABLE