sde-list-download: get rid of bashism to extract first char of filename

Signed-off-by: Alejandro Mery <amery@geeks.cl>

bin/sde-list-download

@@ -85,7 +85,9 @@ $SDEROOT/bin/sde-list-pkg ${config:+-c $config} ${extenders:+-e} ${repositories:
 		fi
 
 		bz2file=$( echo "$gzfile" | sed -e 's,\.gpg$,,' -e 's,\.\(t\?\)\(gz\|Z\)$,.\1bz2,' -e 's,\.tar$,.tar.bz2,' )
-		output="${output:+$output\t}download/$mirror/${bz2file:0:1}/$bz2file"
+		x=$(echo "$bz2file" | cut -c1)
+		x="download/$mirror/$x/$bz2file"
+		output="${output:+$output\t}$x"
 
 		# source location
 		if [ -n "$want_location" ]; then