Fix scan unpickle (crash) as we added a new attribute. Also make a scan opt…

theano/scan_module/scan_op.py

@@ -170,6 +170,12 @@ class Scan(PureOp):
             self._cmodule_key = gof.CLinker().cmodule_key_(local_fgraph, [])
             self._hash_inner_graph = hash(self._cmodule_key)
 
+    def __setstate__(self, d):
+        self.__dict__.update(d)
+        if "allow_gc" not in self.__dict__:
+            self.allow_gc = True
+            self.info['allow_gc'] = True
+
     def make_node(self, *inputs):
         """
         Conventions:

theano/scan_module/scan_opt.py

@@ -798,12 +798,12 @@ class PushOutScanOutput(gof.Optimizer):
             client = outer_var.clients[0][0]
 
             if (client != 'output' and
-                isinstance(client.op, theano.tensor.Subtensor) and
-                isinstance(client.inputs[1], theano.Constant) and
-                client.inputs[1].ndim == 0 and
-                client.inputs[1].value == -1):
-
-                return True
+                isinstance(client.op, theano.tensor.Subtensor)):
+                lst = theano.tensor.subtensor.get_idx_list(
+                    client.inputs, client.op.idx_list)
+                if (len(lst) == 1 and
+                    theano.tensor.extract_constant(lst[0]) == -1):
+                    return True
 
         return False