Merge branch 'nd/clone-connectivity-shortcut' (early part) into maint

Cloning with "git clone --depth N" while fetch.fsckobjects (or
transfer.fsckobjects) is set to true did not tell the cut-off points
of the shallow history to the process that validates the objects and
the history received, causing the validation to fail.

* 'nd/clone-connectivity-shortcut' (early part):
  fetch-pack: prepare updated shallow file before fetching the pack
  clone: let the user know when check_everything_connected is run

diff --cc t/t5500-fetch-pack.sh
Simple merge