Check the right thing to avoid useless recursion in shape_i().

theano/compile/ops.py

@@ -445,7 +445,7 @@ def shape_i(var, i, fgraph=None):
         shape_of = shape_feature.shape_of
 
         def recur(node):
-            if not hasattr(node.outputs[0], 'fgraph'):
+            if not node.outputs[0] in shape_of:
                 for inp in node.inputs:
                     if inp.owner:
                         recur(inp.owner)