net-snmp: rename stop_service to service_stopped

The commands in the function 'stop_service' do not stop the service.
Rather, they are commands that are to be executed when the service has
already been stopped. By renaming the function, the commands are now
executed after the service has been stopped.

Signed-off-by: Florian Eckert <fe@dev.tdt.de>

net/net-snmp/files/snmpd.init

@@ -336,7 +336,7 @@ start_service() {
 	procd_close_instance
 }
 
-stop_service() {
+service_stopped() {
 	[ -f "$CONFIGFILE" ] || return
 	rm -f "$CONFIGFILE"
 	procd_set_config_changed firewall