zdtm: use flake8 to verify zdtm.py
zdtm: use flake8 to verify zdtm.py

and fix various warnings. For example, we mix tab and space indentations.

v2: add flake8.cfg

Cc: Tycho Andersen <10c18fcb898ee6b17d6575d444b125d10b3f4d6a@canonical.com>
Signed-off-by: Andrew Vagin <74c05afa918858348d6db8037d82fa8124870113@virtuozzo.com>
Acked-by: Tycho Andersen <10c18fcb898ee6b17d6575d444b125d10b3f4d6a@canonical.com>
Signed-off-by: Pavel Emelyanov <c9a32589e048e044184536f7ac71ef92fe82df3e@virtuozzo.com>

KKoukiou/criu-remote,KKoukiou/criu-remote,KKoukiou/criu-remote,KKoukiou/criu-remote,KKoukiou/criu-remote,KKoukiou/criu-remote