default linux template memory graph problems

in the default linux template, there is memory usage graph. it plots total & used memory and has y axis min/max set to calculated.

instead, y axis min should be set to 0 and y axis max should be set to total memory item.
total memory should be removed from the graph itself.

in addition to having a better scale for the graph, this will prevent total memory not shown if it's interval is increased from the (very low) default of one hour