Downloads Certificate Revocation Lists

 This tool and associated cron entry ensure that Certificate Revocation
 Lists (CRLs) are periodically retrieved from the web sites of the
 respective Certification Authorities.
 .
 The fetch-crl tool finds all *.crl_url files in the configured CRL
 directory, downloads the CRLs listed in those files and saves them in
 the same directory. The default configuration uses
 /etc/grid-security/certificates as the CRL directory.