[gpad] fix x0,y0 usage in TCreatePrimitives::Ellipse
[gpad] fix x0,y0 usage in TCreatePrimitives::Ellipse

These static variables where not transformed to log scale,
but used during moving of mouse button.
Also not need to store x1,y1 in static variables

olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root