fixed little bug in DebugMode: it was failing to catch an exception when trying to produce C thunks

theano/compile/debugmode.py

@@ -401,7 +401,7 @@ class _Linker(gof.link.LocalLinker):
                 thunk.inputs = node_input_storage
                 thunk.outputs = node_output_storage
                 thunks_c.append(thunk)
-            except utils.AbstractFunctionError:
+            except (NotImplementedError, utils.AbstractFunctionError):
                 thunks_c.append(None)