Fix comment in make-grace helper

helpers/make-grace

@@ -22,7 +22,7 @@ VERSION=1
 . ./config
 
 #Updated copyright file from obtained from
-# http://anonscm.debian.org/cgit/collab-maint/labplot.git/tree/debian/copyright?id=debian/1.6.0.2-3
+# http://ftp.de.debian.org/debian/pool/main/g/grace/grace_5.1.24-3.debian.tar.xz
 # http://anonscm.debian.org/cgit/collab-maint/labplot.git/tree/cephes/COPYING?id=debian/1.6.0.2-3
 
 cp $DATA/copyright debian/copyright