inhibit: ensure no visible changesets are obsolete after an update
When updating to a commit we want to inhibit any obsolete commit affecting
the changeset we are updating to. In other words we don't want any
visible commit to be obsolete.
inhibit: enable direct access from parsing the revset tree
To enable direct access we:
- detect explicit hexadical reference to node in the revset tree
- add these hashes to the static blockers to make them and their parent
visible for the command to run