icedtea7_web: Update from 1.5.2 -> 1.6

pkgs/development/compilers/icedtea-web/default.nix

···
 stdenv.mkDerivation rec {
   name = "icedtea-web-${version}";
 
-  version = "1.5.2";
+  version = "1.6";
 
   src = fetchurl {
     url = "http://icedtea.wildebeest.org/download/source/${name}.tar.gz";
 
-    sha256 = "1wrvl66qj0yhaqqhcq24005ci5sc3w005809cld55iiwagr8z7mj";
+    sha256 = "0z8iirvpciai55s4vhpfkhyx4h4hm6dqy4pg4c61pia3innqd4qn";
   };
 
   buildInputs = [ gtk2 xulrunner zip pkgconfig npapi_sdk ];