Merge branch 'js/diff-files-i-t-a-fix-for-difftool'

"git difftool" has trouble dealing with paths added to the index
with the intent-to-add bit.

* js/diff-files-i-t-a-fix-for-difftool:
  difftool -d: ensure that intent-to-add files are handled correctly
  diff-files --raw: show correct post-image of intent-to-add files