multiattrdict: make multilevel nesting work properly

src/python/m5/util/attrdict.py

@@ -58,7 +58,7 @@ class multiattrdict(attrdict):
         try:
             return super(multiattrdict, self).__getattr__(attr)
         except AttributeError:
-            d = optiondict()
+            d = multiattrdict()
             setattr(self, attr, d)
             return d
 
@@ -86,8 +86,12 @@ if __name__ == '__main__':
     print dir(x)
     print(x)
 
+    print
+    print "multiattrdict"
     x = multiattrdict()
+    x.x.x.x = 9
     x.y.z = 9
     print x
     print x.y
     print x.y.z
+    print x.z.z