evolve: refactor for consistent behavior of evolve when wdp is obsolete This patch make sure that when working directory parent is obsolete `hg evolve` and `hg evolve --all` don't behave differently.

evolve: backout 3027005c42c3 to reintroduce a bug for right fix This patch backout 3027005c42c3 as it was accepted by mistake while it was being "in-discussion" state.