[outlineOTF] Fix bug when checking glyph bounds
[outlineOTF] Fix bug when checking glyph bounds

pen.bounds can be None, not pen.bounds[0], so this was crashing for
glyphs with anchors but no contours.

moyogo/ufo2ft,googlefonts/ufo2ft,jamesgk/ufo2ft,jamesgk/ufo2fdk,googlei18n/ufo2ft