Merge branch 'jt/transfer-fsck-across-packs-fix'

The code to fsck objects received across multiple packs during a single git fetch session has been broken when the packfile URI feature was in use. A workaround has been added by disabling the codepath to avoid keeping a packfile that is too small. * jt/transfer-fsck-across-packs-fix: fetch-pack: do not mix --pack_header and packfile uri