gdk3: remove method redefined warning
gdk3: remove method redefined warning

In GdkCursor, display is a property. see: https://developer.gnome.org/gdk3/3.4/gdk3-Cursors.html

kitachro/ruby-gnome2,kitachro/ruby-gnome2,kitachro/ruby-gnome2,kitachro/ruby-gnome2,kitachro/ruby-gnome2