bug#21457: 25.0.50; vc-test-git03-working-revision test fails

[Eli Zaretskii]

> Date: Sat, 12 Sep 2015 18:36:41 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: 21457@debbugs.gnu.org
> 
> But I still don't understand how this
> 
>         ;; Create empty repository.  Check working revision of
>         ;; repository, should be nil.
>         (make-directory default-directory)
>         (vc-test--create-repo-function backend)
> 
>         ;; nil: CVS Mtn RCS SCCS
>         ;; "0": Bzr Hg SRC SVN
>         ;; "master" or "HEAD": Git
>         (should (eq (vc-working-revision default-directory)
>                     (vc-working-revision default-directory backend)))
> 
> was supposed to work, since "git rev-parse HEAD" fails in an empty
> repository and returns just "HEAD", not a 40-digit hash or "master".

Ah, okay, I get it: vc-working-revision was supposed to fail and
return nil in both cases.  Which makes this test not a very useful
one.  But then how was this supposed to work?

            ;; Register a file.  Check working revision.
            (vc-register
             (list backend (list (file-name-nondirectory tmp-name))))

            ;; nil: Mtn RCS SCCS
            ;; "0": Bzr CVS Hg SRC SVN
            ;; "master" or "HEAD": Git
            (should (eq (vc-working-revision tmp-name)
                        (vc-working-revision tmp-name backend)))
            (should
             (member (vc-working-revision tmp-name) '(nil "0" "master")))