Merge pull request #956 from vlstill/freetds

freetds: Update expression with working url.

pkgs/development/libraries/freetds/default.nix

···
   name = "freetds-0.91";
 
   src = fetchurl {
-    url = ftp://ftp.ibiblio.org/pub/Linux/ALPHA/freetds/stable/freetds-stable.tgz;
+    url = ftp://ftp.astron.com/pub/freetds/stable/freetds-stable.tgz;
     sha256 = "0r946axzxs0czsmr7283w7vmk5jx3jnxxc32d2ncxsrsh2yli0ba";
   };