rc.d/ggated: Simplify service script

- Use the standard *_flags variable for additional flags.
- Style: do not create unnecessary variables
- Do not set the defaults in the service script. This is what
  /etc/defaults/rc.conf is for.
- Do not set additional flags via commands_args. ggated_flags are
  already included in the final invocation. See rc.subr(8) for details.
- Document the meaning of ggated_config in /etc/defaults/rc.conf.

Approved by:	eugen (src)
Fixes:		c068632981 Add ggated rc script
Differential Revision:	https://reviews.freebsd.org/D34439

libexec/rc/rc.conf

@@ -297,8 +297,8 @@ hastd_enable="NO"		# Run the HAST daemon (YES/NO).
 hastd_program="/sbin/hastd"	# path to hastd, if you want a different one.
 hastd_flags=""			# Optional flags to hastd.
 ggated_enable="NO"		# Run the ggate daemon (YES/NO).
-ggated_config="/etc/gg.exports"
-ggated_params=""		# Extra parameters like which port to bind to.
+ggated_config="/etc/gg.exports"	# ggated(8) exports file.
+ggated_flags=""			# Extra parameters like which port to bind to.
 ctld_enable="NO"		# CAM Target Layer / iSCSI target daemon.
 local_unbound_enable="NO"	# Local caching resolver
 local_unbound_tls="NO"		# Use DNS over TLS

libexec/rc/rc.d/ggated

@@ -12,10 +12,8 @@ command="/sbin/${name}"
 pidfile="/var/run/${name}.pid"
 
 load_rc_config $name
-params="${ggated_params}"
-config="${ggated_config:-/etc/gg.exports}"
-required_files="${config}"
+required_files="${ggated_config}"
 
-command_args="${params} ${config}"
+command_args="${ggated_config}"
 
 run_rc_command "$1"