removed soon-to-be-universally-fixed defaults

common/lib/xmodule/xmodule/templates/problem/drag_and_drop.yaml

 ---
 metadata:
     display_name: Drag and Drop
-    rerandomize: never
-    showanswer: finished
+    markdown: !!null    
 data: |
     <problem>
         Here's an example of a "Drag and Drop" question set. Click and drag each word in the scrollbar below, up to the numbered bucket which matches the number of letters in the word. 
@@ -40,5 +39,3 @@ data: |
             </answer>
         </customresponse>
     </problem>
-
-children: []