This adds new keywords to rc / service to enable or disable a services's rc.conf(5) variable and "rcdelete" to remove the variable.
When the "service_use_rcconfd" variable in rc.conf is set to "YES" (default is no) the service variables are added to a separate
file in /etc/rc.conf.d/. If the file is empty after issuing "service $foo rcdelete", the file gets deleted.