Skylark: type of None is NoneType (instead of None), for consistency with Python.

--
MOS_MIGRATED_REVID=93120393
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/EvalUtils.java b/src/main/java/com/google/devtools/build/lib/syntax/EvalUtils.java
index ca73ea4..bdc0fb6 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/EvalUtils.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/EvalUtils.java
@@ -273,7 +273,7 @@
     } else if (c.equals(Boolean.class)) {
       return "bool";
     } else if (c.equals(Void.TYPE) || c.equals(Environment.NoneType.class)) {
-      return "None";
+      return "NoneType";
     } else if (List.class.isAssignableFrom(c)) {
       // NB: the capital here is a subtle way to distinguish java Tuple and java List
       // from native SkylarkList tuple and list.