1.74.2 is no longer available from the leptonica website. But anyway, it seems safer going forward to download it from github. It's https, and it won't disappear as easily. Also, this is the same source used by travis, so there's less chance of shipping something untested.

The newer version contains fixes for the pixUnsharpMaskingGray*
functions which are relevant for Tesseract (used in ImageData::PreScale
which calls pixScale).
Signed-off-by: NStefan Weil <sw@weilnetz.de>