Merge pull request #904 from jmaas/master

PEP8 - cobbler/modules/sync_post_restart_services.py
Merge pull request #905 from jmaas/master

PEP8 - cobbler/modules/serializer_mysql.py
Merge pull request #906 from jmaas/master

PEP8 - cobbler/modules/serializer_mongodb.py
Merge pull request #907 from jmaas/master

PEP8 - cobbler/modules/serializer_couch.py