Revert "leptonica: md5sum of upstream changed"

The issue is that the upstream package has been bworked (it is not
a .tar.gz in reality), which explains why the md5sum changed).

The source code is also available on github, but with a 3rd md5sum.

This reverts commit 2f705697.

component/leptonica/buildout.cfg

@@ -12,7 +12,7 @@ extends =
 [leptonica]
 recipe = slapos.recipe.cmmi
 url = http://www.leptonica.com/source/leptonica-1.76.0.tar.gz
-md5sum = cea221c4b93e370cc7b478b3da291abe
+md5sum = a263a5e4f7e8f8a661fb121a265d2d20
 shared = true
 configure-options =
   --disable-static