Merge branch 'bc/repack'

* bc/repack: Documentation/git-repack.txt: document new -A behaviour let pack-objects do the writing of unreachable objects as loose objects add a force_object_loose() function builtin-gc.c: deprecate --prune, it now really has no effect git-gc: always use -A when manually repacking repack: modify behavior of -A option to leave unreferenced objects unpacked Conflicts: builtin-pack-objects.c