git: restore basic functionality after b3040b6739ce
We don't yet have a formal interface for the changelog, but it's
mostly specified. Sadly, b3040b6739ce added a semi-private pseudo-enum
that we need to cope with, so it's probably high time that someone
(me?) attempts to define that interface to prevent future backsliding.
Differential Revision: https://phab.mercurial-scm.org/D8992
(binary:application/octet-stream)