rebase: properly handle unrebased revision between rebased one With rebase taking multiple roots it is possible to have revision in the "rebase domain" not rebased themself. We do not want rebased revision above them to be detached. We want such revision to be rebased on the nearest rebased ancestors. This allows to preserve the topology of the rebase set as much a possible To achieve this we introduce a new state `revignored` which informs `defineparents` of the situation. The test in `test-rebase-obsolete.t` was actually wrote and his now fixed.