fix typo that affected error handling for file upload/download
fix typo that affected error handling for file upload/download

StanfordBioinformatics/loom,StanfordBioinformatics/xppf,StanfordBioinformatics/loom,StanfordBioinformatics/loom,StanfordBioinformatics/xppf,StanfordBioinformatics/xppf,StanfordBioinformatics/loom,StanfordBioinformatics/xppf