Fix accidental removal of devfs_rulesets on jail stop
Pulls in a bugfix that has been merged upstream.
This bug caused manually configured devfs_rulesets to get deleted on jail
stop, causing jails to come up with a default devfs rules on next start,
which can be a nuisance or even dangerous, depending on the specific setup.
Also adds a minimum devfs_ruleset id for dynamically created devfs rulesets
and fixes a devfs_ruleset resource leak when using plugins.
Take maintainership, as suggested by araujo@ (thanks for taking care of that
port for so long!).
Approved by: araujo (maintainer)