libproxy: update from 0.4.7 to 0.4.11, potentially fixes CVE-2012-4504

pkgs/development/libraries/libproxy/default.nix

···
 {stdenv, fetchurl, cmake, zlib}:
 
 stdenv.mkDerivation rec {
-  name = "libproxy-0.4.7";
+  name = "libproxy-0.4.11";
   src = fetchurl {
     url = "http://libproxy.googlecode.com/files/${name}.tar.gz";
-    sha256 = "15rp97g3s2xkc842p5qfm8kx3p4awvrwrpl6w71a76qk224abq4g";
+    sha256 = "0jw6454gxjykmbnbh544axi8hzz9gmm4jz1y5gw1hdqnakg36gyw";
   };
   buildInputs = [cmake zlib];
 }