La solución es desinstalar el módulo
yum remove mod_nss
Ejemplo de error:
[Mon Apr 29 13:37:24 2013] [error] Certificate not verified: 'Server-Cert'
[Mon Apr 29 13:37:24 2013] [error] SSL Library Error: -8181 Certificate has expired
[Mon Apr 29 13:37:24 2013] [error] Unable to verify certificate 'Server-Cert'. Add "NSSEnforceValidCerts off" to nss.conf so the server can start until the problem can be resolved.
Bug en RH:
https://bugzilla.redhat.com/show_bug.cgi?format=multiple&id=711085