Don't run dist test for ruby-gtk3 on Ruby 1.8
Don't run dist test for ruby-gtk3 on Ruby 1.8

ruby-gtk3 doesn't support Ruby 1.8

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