Merge branch 'ds/diff-lazy-fetch-with-name-only-fix' into next

Running "git diff" with "--name-only" and other options that allows
us not to look at the blob contents, while objects that are lazily
fetched from a promisor remote, caused use-after-free, which has
been corrected.

* ds/diff-lazy-fetch-with-name-only-fix:
  diff: avoid segfault with freed entries