mod_ssl: Don't enable CRL checks/flags by default.

(follow up/fix to r1748338 committed in 2.4.21)

Submitted by: ylavic
Reviewed by: icing, minfrin


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1748442 13f79535-47bb-0310-9956-ffa450edef68