Revert null change

hexrd/config/utils.py

@@ -8,6 +8,13 @@
                             "sfacmin", "sfacmax", "pintmin", "pintmax"]
 )
 
+# Converting to none threw errors, maybe change later
+class Null():
+    pass
+
+null = Null()
+
+
 def merge_dicts(a, b):
     """Return a merged dict, updating values from `a` with values from `b`."""
     # need to pass a deep copy of a at the top level only: