close runner properly

Author: carlosuc3m

src/main/java/io/bioimage/modelrunner/pytorch/PytorchInterface.java

@@ -458,11 +458,11 @@ else if (task.status == TaskStatus.FAILED)
 			else if (task.status == TaskStatus.CRASHED)
 				throw new RuntimeException();
 			this.runner.close();
+			this.runner = null;
 			return;
 		} else if (this.interprocessing) {
 			return;
 		}
-		model = null;
 		if (model != null) 
 			model.close();
 		model = null;