vcs-to-changelog: Expect spaces in file names Reported by Thierry Bothorel <thierry.bothorel@zaclys.net> in <https://lists.gnu.org/archive/html/bug-gnulib/2020-11/msg00040.html>, * build-aux/vcstocl/vcs_git.py (exec_git_cmd): Do not transform tabs to spaces. (list_changes): Use tabs to identify file names.