Merge branch 'jt/repack-promisor-packs'

After a partial clone, repeated fetches from promisor remote would have accumulated many packfiles marked with .promisor bit without getting them coalesced into fewer packfiles, hurting performance. "git repack" now learned to repack them. * jt/repack-promisor-packs: repack: repack promisor objects if -a or -A is set repack: refactor setup of pack-objects cmd