git-merge-changelog: Remove module. It is now available through $ git clone https://git.savannah.gnu.org/git/vc-changelog.git see https://gitweb.git.savannah.gnu.org/gitweb/?p=vc-changelog.git . * lib/git-merge-changelog.c: Remove file. * modules/git-merge-changelog: Remove file. * NEWS: Mention the change.