bundlerepo: retract phase boundary This patch makes bundrepo retract the phase boundary for new commits to 'draft' status, which is consistent with the behavior of 'hg unbundle'. The old behavior was for commits to appear with the same phase as their nearest ancestor in the base repository. This affects several classes of operation: * Inspecting a bundle with the -B flag * Treating a bundle file as a peer (old: everything public, new: everything draft) * Incoming command (neither old or new behavior is sensible -- fixed in next patch)