Add SSLCARevocationCheck directive to default mod_ssl config

#   Certificate Revocation Lists (CRL):

#   Set the CA revocation path where to find CA CRLs for client

#   authentication or alternatively one huge file containing all

#   of them (file must be PEM encoded)

#   of them (file must be PEM encoded).

#   The CRL checking mode needs to be configured explicitly

#   through SSLCARevocationCheck (defaults to "none" otherwise).

#   Note: Inside SSLCARevocationPath you need hash symlinks

#         to point to the certificate files. Use the provided

#         Makefile to update the hash symlinks after changes.

#SSLCARevocationPath "@exp_sysconfdir@/ssl.crl"

#SSLCARevocationFile "@exp_sysconfdir@/ssl.crl/ca-bundle.crl"

#SSLCARevocationCheck chain

#   Client Authentication (Type):

#   Client certificate verification type and depth.  Types are