Moved 'maintainers' attribute into the meta section of the expression.

I've also set the 'platforms' attribute to ensure that Hydra actually
builds these packages. Thanks to Lluís Batlle i Rossell for pointing out
these mistakes.

svn path=/nixpkgs/trunk/; revision=21688

pkgs/applications/science/math/maxima/default.nix

@@ -17,7 +17,7 @@ stdenv.mkDerivation {
   meta = {
     description = "Maxima computer algebra system";
     homepage = http://maxima.sourceforge.net;
+    platforms = stdenv.lib.platforms.all;
+    maintainers = [ stdenv.lib.maintainers.simons ];
   };
-
-  maintainers = [ stdenv.lib.maintainers.simons ];
 }