Merge branch 'jt/no-abuse-alternate-odb-for-submodules'

Follow through the work to use the repo interface to access submodule objects in-process, instead of abusing the alternate object database interface. * jt/no-abuse-alternate-odb-for-submodules: submodule: trace adding submodule ODB as alternate submodule: pass repo to check_has_commit() object-file: only register submodule ODB if needed merge-{ort,recursive}: remove add_submodule_odb() refs: peeling non-the_repository iterators is BUG refs: teach arbitrary repo support to iterators refs: plumb repo into ref stores