fix using bilevel tiff in pdf output
fix using bilevel tiff in pdf output

tesseract-ocr/tesseract,amitdo/tesseract,UB-Mannheim/tesseract,UB-Mannheim/tesseract,amitdo/tesseract,stweil/tesseract,stweil/tesseract,UB-Mannheim/tesseract,tesseract-ocr/tesseract,stweil/tesseract,tesseract-ocr/tesseract,amitdo/tesseract,amitdo/tesseract,UB-Mannheim/tesseract,amitdo/tesseract,stweil/tesseract,tesseract-ocr/tesseract,UB-Mannheim/tesseract,stweil/tesseract,tesseract-ocr/tesseract