Merge branch 'jk/index-pack-reduce-recheck' into maint

Disable "have we lost a race with competing repack?" check while
receiving a huge object transfer that runs index-pack.

* jk/index-pack-reduce-recheck:
  index-pack: avoid excessive re-reading of pack directory

diff --cc builtin/index-pack.c
Simple merge

diff --cc cache.h
Simple merge

diff --cc sha1_file.c
Simple merge