fix bash completion prints fb path at new terminals on Mac
fix bash completion prints fb path at new terminals on Mac

(issue #2466)

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