fix issue #820: deal with multiply encoded spacing glyphs
fix issue #820: deal with multiply encoded spacing glyphs

Addressing @khaled's comment at: https://github.com/googlefonts/fontbakery/pull/847#issuecomment-233526587

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