Merge branch 'tb/commit-graph-use-tempfile'

"git update-server-info" and "git commit-graph --write" have been
updated to use the tempfile API to avoid leaving cruft after
failing.

* tb/commit-graph-use-tempfile:
  server-info.c: remove temporary info files on exit
  commit-graph.c: remove temporary graph layers on exit

diff --cc commit-graph.c
Simple merge