Fix fix-ttf-vmet.py labels and ymax count
Fix fix-ttf-vmet.py labels and ymax count

jessamynsmith/fontbakery,graphicore/fontbakery,vitalyvolkov/fontbakery,vitalyvolkov/fontbakery,graphicore/fontbakery,moyogo/fontbakery,googlefonts/fontbakery,moyogo/fontbakery,davelab6/fontbakery,googlefonts/fontbakery,vitalyvolkov/fontbakery,googlefonts/fontbakery,graphicore/fontbakery,moyogo/fontbakery