Merge branch 'jt/fetch-remove-lazy-fetch-plugging'

"git fetch" codepath had a big "do not lazily fetch missing objects
when I ask if something exists" switch.  This has been corrected by
marking the "does this thing exist?" calls with "if not please do not
lazily fetch it" flag.

* jt/fetch-remove-lazy-fetch-plugging:
  promisor-remote: remove fetch_if_missing=0
  clone: remove fetch_if_missing=0
  fetch: remove fetch_if_missing=0

diff --cc builtin/clone.c
Simple merge

diff --cc builtin/fetch.c
Simple merge

diff --cc fetch-pack.c
Simple merge

diff --cc t/t5616-partial-clone.sh
Simple merge