Merge branch 'ds/fsck-pack-revindex'

"git fsck" learned to validate the on-disk pack reverse index files.

* ds/fsck-pack-revindex:
  fsck: validate .rev file header
  fsck: check rev-index position values
  fsck: check rev-index checksums
  fsck: create scaffolding for rev-index checks

diff --cc builtin/fsck.c
Simple merge

diff --cc pack-bitmap.c
Simple merge

diff --cc pack-revindex.c
index db282dac8d6ce93761e2569d4089157802d65797,146334e2c96df2e60d164b1f126295ca18d34e93..1f51b712e879e401e9b308d993a2b810460f01e3
--- 1/pack-revindex.c
--- 2/pack-revindex.c
+++ b/pack-revindex.c
@@@ -1,12 -1,11 +1,13 @@@
 -#include "cache.h"
 +#include "git-compat-util.h"
  #include "gettext.h"
  #include "pack-revindex.h"
 +#include "object-file.h"
  #include "object-store.h"
  #include "packfile.h"
 +#include "trace2.h"
  #include "config.h"
  #include "midx.h"
+ #include "csum-file.h"
  
  struct revindex_entry {
        off_t offset;