Added variable in RRDTool class to store the value of 'rrd_use_poller_output'.
Added variable in RRDTool class to store the value of 'rrd_use_poller_output'.

howardjones/network-weathermap,howardjones/network-weathermap,howardjones/network-weathermap,howardjones/network-weathermap,howardjones/network-weathermap,howardjones/network-weathermap