Detach rpzs and catzs from the previous view
When switching to a new view during a reconfiguration (or reverting to the old view), detach the 'rpzs' and 'catzs' from the previuos view.
The 'catzs' case was earlier solved slightly differently, by detaching from the new view when reverting to the old view, but we can not solve this the same way for 'rpzs', because now in BIND 9.19 and BIND 9.18 a dns_rpz_shutdown_rpzs() call was added in view's destroy() function before detaching the 'rpzs', so we can not leave the 'rpzs' attached to the previous view and let it be shut down when we intend to continue using it with the new view.
Instead, "re-fix" the issue for the 'catzs' pointer the same way as for 'rpzs' for consistency, and also because a similar shutdown call is likely to be implemented for 'catzs' in the near future.
Closes #3880 (closed)