Typo fix.

theano/tensor/nnet/nnet.py

@@ -1063,7 +1063,7 @@ def local_advanced_indexing_crossentropy_onehot_grad(node):
 
             # set out_grad according to the numerator, it may be divided later
             # num should be a vector or a scalar
-            if numpy.ndim==1 or numpy.all(num.broadcastable):
+            if num.ndim==1 or numpy.all(num.broadcastable):
                 out_grad *= -num
             else:
                 return