da45b4da83
This adds new keywords to rc/service to enable/disable a service's rc.conf(5) variable and "delete" to remove the variable. When the "service_delete_empty" variable in rc.conf(5) is set to "YES" (default is "NO") an rc.conf.d file (in /etc/ or /usr/local/etc) is deleted if empty after modification using "service $foo delete". Submitted by: lme (modified) Reviewed by: 0mp (previous version), lme, bcr Relnotes: yes Sponsored by: Smule, Inc. Differential Revision: https://reviews.freebsd.org/D17113