Add host_name value for the plugin config so the graphs are seperated out from the polling host

plugins/hg612_errors

@@ -35,6 +35,7 @@ fi
 
 if [ "$1" = "config" ]; then
 
+	echo "host_name hg612"
 	echo "graph_title Errors"
 	echo "graph_args --base 1000"
 	echo 'graph_vlabel errors down (-) / up (+) per ${graph_period}'