package/python-docutils: add upstream patch to build without setuptools

An upstream patch to enable building without setuptools is added.
The original commit is adjusted slightly to fit the current version.

Fixes:
 - http://autobuild.buildroot.net/results/8f3c01f0e286c6b15c8c973f91dd69ee816a58b9



Signed-off-by: Asaf Kahlon <asafka7@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>