Merge branch 'mm/fetch-show-error-message-on-unadvertised-object' into maint

"git fetch" that requests a commit by object name, when the other
side does not allow such an request, failed without much
explanation.

* mm/fetch-show-error-message-on-unadvertised-object:
  fetch-pack: add specific error for fetching an unadvertised object
  fetch_refs_via_pack: call report_unmatched_refs
  fetch-pack: move code to report unmatched refs to a function

diff --cc remote.h
Simple merge

diff --cc t/t5516-fetch-push.sh
Simple merge

diff --cc transport.c
Simple merge