pep8: fix E711
pep8: fix E711

Fix pep8 E711
E711: comparison to None should be ‘if cond is None:’

akbooer/whisper,graphite-project/whisper,deniszh/whisper,cbowman0/whisper,kerlandsson/whisper,graphite-server/whisper,obfuscurity/whisper,penpen/whisper,jjneely/whisper,piotr1212/whisper,alexandreboisvert/whisper