leptonica download url changed

[anouar1991]

alfresco-simple-ocr/docker/pdfsandwich-1.6-centos-7/Dockerfile

Line 8 in b789a5e

&& wget http://www.leptonica.com/source/leptonica-1.74.4.tar.gz \

leptonica has moved from .com to org. which cause the current download link to produce an error while trying to extract the downloaded file:

tar zfxa leptonica-1.74.4.tar.gz

gzip: stdin: not in gzip format
tar: Child returned status 1
tar: Error is not recoverable: exiting now

because it is actually downloading an HTML page

# file leptonica-1.74.4.tar.gz
leptonica-1.74.4.tar.gz: HTML document, ASCII text

changing .com to .org will fix the problem
http://www.leptonica.org/source/leptonica-1.74.4.tar.gz