simplified the nan comparison for the regtests

Author: carlocamilloni

regtest/scripts/fixzeroes.sh

@@ -6,7 +6,6 @@ grep -E '[^[:print:]]' $file 2> /dev/null && exit 0
 
 sed "s/-\(0\.0*0 \)/ \1/g; 
      s/-\(0\.0*0$\)/ \1/g" $file > $file.$$.tmp
-sed "s/-\(nan \)/\1/g; 
-     s/-\(nan$\)/\1/g" $file.$$.tmp > $file.$$.tmp2
+sed "s/-nan/nan/g" $file.$$.tmp > $file.$$.tmp2
 mv $file.$$.tmp2 $file