python-daemon: add missing dependencies

python-daemon package mentions python-docutils in both setup_requires
and instal_requires fields. So add related dependencies.

Fixes:
http://autobuild.buildroot.net/results/0c3/0c3866038f7c40888e5e440f7a720fc614a6b1ba/
http://autobuild.buildroot.net/results/5d8/5d817bddeff5bb49ed31c6a1d111974c358ef96c/


and many more.

Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>