Git.pm: fix bare repository search with Directory option

When opening a bare repository like: Git->repository(Directory => '/path/to/bare.git'); we will incorrectly point the repository object at the _current_ directory, not the one specified by the option. The bug was introduced by 20da61f25f (Git.pm: trust rev-parse to find bare repositories, 2022-10-22). Before then, we'd ask "rev-parse --git-dir" if it was a Git repo, and if it returned anything, we'd correctly convert that result to an absolute path using File::Spec and Cwd::abs_path(). If it didn't, we'd guess it might be a bare repository and find it ourselves, which was wrong (rev-parse should find even a bare repo, and our search circumvented some of its rules). That commit dropped most of the custom bare-repo search code in favor of using "rev-parse --is-bare-repository" and trusting the "--git-dir" it returned. But it mistakenly left some of the bare-repo code path in place, which was now broken. That code calls Cwd::abs_path($dir); prior to 20da61f25f $dir contained the "Directory" option the user passed in. But afterwards, it contains the output of "rev-parse --git-dir". And since our tentative rev-parse command is invoked after changing directory, it will always be the relative path "."! So we'll end up with the absolute path of the process's current directory, not the Directory option the caller asked for. So the non-bare case is correct, but the bare one is broken. Our tests only check the non-bare one, so we didn't notice. We can fix this by running the same absolute-path fixup code for both sides. Helped-by: Rodrigo <rodrigolive@gmail.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>