fix crash when failing to parse ttfautohint version strings
fix crash when failing to parse ttfautohint version strings

issue #1063

moyogo/fontbakery,graphicore/fontbakery,googlefonts/fontbakery,moyogo/fontbakery,graphicore/fontbakery,googlefonts/fontbakery,moyogo/fontbakery,googlefonts/fontbakery,graphicore/fontbakery