Make GAF scheme dir compatible with Lepton EDA

[أحمد المحمودي (Ahmed El-Mahmoudy)]

Hello,

  Debian has replaced gEDA/gaf with Lepton EDA, which is a fork of gEDA. So when I built pcb using --with-gaf-datadir=/usr/share/lepton-eda, it installed the scheme addition to /usr/share/lepton-eda/gEDA/scheme dir ! Which is contrary to what I expected it to do (ie. install to /usr/share/lepton-eda/scheme). So I prepared a patch to fix this, the patch expects GAFDATADIR to include the gEDA (or whatever equivalent tool name). I hope you would accept the patch.