Merge branch 'bp/read-index-from-skip-verification'

Drop (perhaps overly cautious) sanity check before using the index
read from the filesystem at runtime.

* bp/read-index-from-skip-verification:
  read_index_from(): speed index loading by skipping verification of the entry order

diff --cc builtin/fsck.c
Simple merge

diff --cc cache.h
Simple merge

diff --cc read-cache.c
Simple merge