Merge pull request #337 from astrot1988/fix_subgraph

fix: subgraph remove output

src/nodes/base.js

@@ -264,7 +264,7 @@
     };
 
     Subgraph.prototype.onSubgraphRemovedOutput = function(name) {
-        var slot = this.findInputSlot(name);
+        var slot = this.findOutputSlot(name);
         if (slot == -1) {
             return;
         }