Ticket 49257 - Reject dbcachesize updates while auto cache sizing is enabled
Description: We should reject updates to nsslapd-dbcachesize while auto cache sizing
is in effect. This is because at startup we would overwrite the
manually set dbcache size anyway. It would never take effect, so it
should be rejected.
https://pagure.io/389-ds-base/issue/49257
Reviewed by: tbordaz & firstyear(Thanks!!)
(cherry picked from commit 910a4ce2b5a19fa8de939519ac865a56feb7b626)