Issue #1602 - Numeric selection size wrong after switching tools

In GimpToolRectangle, call gimp_tool_rectangle_update_options()
when the "[xy][12]" properties change, so that the "x", "y",
"width", and "height" properties are updated accordingly.

In particular, we set these properties when committing an empty
rectangle select tool, to init the rectangle to the current
selection bounds, and this call is necessary so that the "x", "y",
"width", and "height" tool options are properly updated as well.

app/display/gimptoolrectangle.c

@@ -1069,6 +1069,8 @@ gimp_tool_rectangle_notify (GObject    *object,
       ! strcmp (pspec->name, "y2"))
     {
       gimp_tool_rectangle_update_int_rect (rectangle);
+
+      gimp_tool_rectangle_update_options (rectangle);
     }
   else if (! strcmp  (pspec->name, "x") &&
            ! PIXEL_FEQUAL (private->x1, private->x))