Description of problem:
If you set nsslapd-readonly=on and restart the instance, ns-slapd consumes 100% CPU, no ports are opened, and the service is unavailable.

Version-Release number of selected component (if applicable):
389-ds-base-1.4.3.13-1.module+el8dsrv+8334+69a46a2e.x86_64

How reproducible:
Always.

Steps to Reproduce:
1. dsconf -D "cn=Directory Manager" ldap://server.example.com config replace nsslapd-readonly=on
2. systemctl restart dirsrv@instance_name

Actual results:
The systemctl command never ends, ns-slapd consumes 100% CPU, no ports are opened. The service is not available, and no meaningful error is logged.

Expected results:
If it's expected that the instance can't be (re-)started in read-only mode, then starting the service should fail and a meaningful information should be logged.

If it's expected that the instance starts, then ns-slapd should not hang and start successfully in read-only mode.