tesseractmain: EXIT_FAILURE if tesseract is called without arguments
tesseractmain: EXIT_FAILURE if tesseract is called without arguments

When Tesseract is called without any argument, the help message is still
printed, but the exit status no longer indicates success (EXIT_OK).

Signed-off-by: Stefan Weil <8d4c780fcfdc41841e5070f4c43da8958ba6aec0@weilnetz.de>

amitdo/tesseract,stweil/tesseract,jbarlow83/tesseract,UB-Mannheim/tesseract,UB-Mannheim/tesseract,UB-Mannheim/tesseract,stweil/tesseract,jbarlow83/tesseract,tesseract-ocr/tesseract,amitdo/tesseract,stweil/tesseract,amitdo/tesseract,amitdo/tesseract,tesseract-ocr/tesseract,jbarlow83/tesseract,tesseract-ocr/tesseract,jbarlow83/tesseract,amitdo/tesseract,tesseract-ocr/tesseract,UB-Mannheim/tesseract,tesseract-ocr/tesseract,UB-Mannheim/tesseract,stweil/tesseract,stweil/tesseract,jbarlow83/tesseract