remove unused variable
remove unused variable

post.isFixedPitch is always False unless postscriptIsFixedPitch is provided in
fontinfo.plist.

Perhaps the previous code was checking if the font was actually monospaced.
But it was later on changed to use default to False if missing.

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