make it safer in case the model has multiple outputs

Author: JanFSchulte

hls4ml/model/graph.py

@@ -565,9 +565,9 @@ def remove_node(self, node, rewire=True):
                     if outputs[0] == nxt_inp:
                         next_node.inputs[i] = inputs[0]
 
-        if node.outputs[0] == self.outputs[0]:
+        if node.outputs[0] in self.outputs:
             prev_node = node.get_input_node(node.inputs[0])
-            self.outputs[0] = prev_node.outputs[0]
+            self.outputs[self.outputs.index(node.outputs[0])] = prev_node.outputs[0]
         del self.output_vars[node.outputs[0]]
         del self.graph[node.name]