Merge branch 'fm/fetch-raw-sha1'

"git upload-pack" that serves "git fetch" can be told to serve
commits that are not at the tip of any ref, as long as they are
reachable from a ref, with uploadpack.allowReachableSHA1InWant
configuration variable.

* fm/fetch-raw-sha1:
  upload-pack: optionally allow fetching reachable sha1
  upload-pack: prepare to extend allow-tip-sha1-in-want
  config.txt: clarify allowTipSHA1InWant with camelCase

diff --cc Documentation/config.txt
Simple merge

diff --cc upload-pack.c
Simple merge