evolve: fix the inconsistent behaviour of prune (issue6137)
Let's not update to any revision when working directory parent
is not related to the revision being pruned.
Changes in test file demonstrate the fixed behaviour.
$ cat >> $HGRCPATH <<EOF
> [ui]
> logtemplate={rev}:{node|short}[{bookmarks}] ({obsolete}/{phase}) {desc|firstline}\n
> [extensions]
> EOF
$ echo "evolve=$(echo $(dirname $TESTDIR))/hgext3rd/evolve/" >> $HGRCPATH
$ mkcommit() {
> echo "$1" > "$1"
> hg add "$1"
> hg ci -m "add $1"
> }
$ hg init repo
$ cd repo
$ mkcommit a
$ mkcommit b
test disabling commands
$ cat >> .hg/hgrc <<EOF
> [experimental]
> evolution=createmarkers
> allowunstable
> exchange
> EOF
$ hg prune
hg: unknown command 'prune'
(use 'hg help' for a list of commands)
[255]