use self.items instead of iteritems, to fix error

Author: bedroge

easybuild/base/frozendict.py

@@ -52,7 +52,7 @@ def __repr__(self):
 
     def __hash__(self):
         if self.__hash is None:
-            self.__hash = reduce(operator.xor, map(hash, self.iteritems()), 0)
+            self.__hash = reduce(operator.xor, map(hash, self.items()), 0)
 
         return self.__hash