Merge branch 'jt/lazy-fetch'

Updates to on-demand fetching code in lazily cloned repositories. * jt/lazy-fetch: fetch: no FETCH_HEAD display if --no-write-fetch-head fetch-pack: remove no_dependents code promisor-remote: lazy-fetch objects in subprocess fetch-pack: do not lazy-fetch during ref iteration fetch: only populate existing_refs if needed fetch: avoid reading submodule config until needed fetch: allow refspecs specified through stdin negotiator/noop: add noop fetch negotiator