Merge branch 'jt/non-blob-lazy-fetch'

Merge branch 'jt/non-blob-lazy-fetch'

A partial clone that is configured to lazily fetch missing objects
will on-demand issue a "git fetch" request to the originating
repository to fill not-yet-obtained objects.  The request has been
optimized for requesting a tree object (and not the leaf blob
objects contained in it) by telling the originating repository that
no blobs are needed.

* jt/non-blob-lazy-fetch:
  fetch-pack: exclude blobs when lazy-fetching trees
  fetch-pack: avoid object flags if no_dependents