fixed memory aliasing in destroyhandler (probably didn't cause bug

theano/gof/destroyhandler.py

@@ -644,27 +644,28 @@ class DestroyHandler(toolbox.Bookkeeper):
         <unknown>
     """
 
+
+    def __init__(self, do_imports_on_attach=True):
+        self.fgraph = None
+        self.do_imports_on_attach = do_imports_on_attach
+
         """maps every variable in the graph to its "foundation" (deepest
         ancestor in view chain)
         TODO: change name to var_to_vroot"""
-    droot = {}
+        self.droot = OrderedDict()
 
         """maps a variable to all variables that are indirect or direct views of it
          (including itself)
          essentially the inverse of droot
         TODO: do all variables appear in this dict, or only those that are foundations?
-    TODO: do only destoryed variables go in here? one old docstring said so
+        TODO: do only destroyed variables go in here? one old docstring said so
         TODO: rename to x_to_views after reverse engineering what x is"""
-    impact = {}
+        self.impact = OrderedDict()
 
         """if a var is destroyed, then this dict will map
         droot[var] to the apply node that destroyed var
         TODO: rename to vroot_to_destroyer"""
-    root_destroyer = {}
-
-    def __init__(self, do_imports_on_attach=True):
-        self.fgraph = None
-        self.do_imports_on_attach = do_imports_on_attach
+        self.root_destroyer = OrderedDict()
 
     def on_attach(self, fgraph):
         """