Ticket 47891 - Admin Server reconfig breaks SSL config
    
    Description:
    1) Use mkdtemp to reduce the risk to disclose the sec file backup
       location that is in the same file system as the original files
       exist.
    2) reconfig_backup_secfiles and reconfig_restore_secfiles expect
       the admin config dir, e.g., "/etc/dirsrv/admin-serv" or the dir
       specified by the environment variable.
    3) Update (--update) did not call reconfig_restore_secfiles in which
       restores and delete the backup dir.
    4) If creating or accessing the sec backup dir fails, it issues a
       fatal error and quits the reconfiguration.
    
    https://fedorahosted.org/389/ticket/47891
    
    Reviewed by rmeggins@redhat.com (Thank you, Rich!!)