spark_16: removed ancient (insecure) version

pkgs/applications/networking/cluster/spark/default.nix

···
 
 let
   versionMap = {
-    "1.6.3" = {
-                hadoopVersion = "cdh4";
-                sparkSha256 = "00il083cjb9xqzsma2ifphq9ggichwndrj6skh2z5z9jk3z0lgyn";
-              };
     "2.2.0" = {
                 hadoopVersion = "hadoop2.7";
                 sparkSha256 = "0wjjn2pgalrcji8avhj5d48kl1mf7rhrdxhzf29dbiszq4fkx0s6";

pkgs/top-level/all-packages.nix

···
   self = callPackage_i686 ../development/interpreters/self { };
 
   spark = spark_22;
-  spark_16 = callPackage ../applications/networking/cluster/spark { version = "1.6.3"; };
   spark_22 = callPackage ../applications/networking/cluster/spark { version = "2.2.0"; };
 
   spidermonkey_1_8_5 = callPackage ../development/interpreters/spidermonkey/1.8.5.nix { };