evolve: show cset hash in "update to local conflict" message

evolve: use hg.updaterepo() instead of hg.update() to hide stats

evolve: fix the conflicts error message during content-divergence resolution Before last patch, we didn't had an automated way to continue an interrupted content-divergence resolution and we used to show a very long error message on how to continue manually. This patch replaces that long error message with nice small message which tells how to continue and how to abort. We still show `hg update -C .` to abort as we need to test and make `--abort` work in case of content-divergence.