Merge branch 'jt/avoid-lazy-fetch-commits'

Even in a repository with promisor remote, it is useless to attempt to lazily attempt fetching an object that is expected to be commit, because no "filter" mode omits commit objects. Take advantage of this assumption to fail fast on errors. * jt/avoid-lazy-fetch-commits: commit: don't lazy-fetch commits object-file: emit corruption errors when detected object-file: refactor map_loose_object_1() object-file: remove OBJECT_INFO_IGNORE_LOOSE