[9.20] fix: usr: Fix a possible catalog zone issue during reconfiguration

The :iscman:`named` process could terminate unexpectedly during
reconfiguration when a catalog zone update was taking place at
the same time. This has been fixed.

Backport of MR !11366

Merge branch 'backport-aram/catz-reconfig-crash-fix-9.20' into 'bind-9.20'

See merge request isc-projects/bind9!11386