Enable H405 PEP8 check

Fixes files with the PEP8 error:

    H405  multi line docstring summary not separated with an empty line

and enables the PEP8 check in tox.ini.

Change-Id: I632c89e2a1783be8305a8a8cea7ae9d3bb55b62c
Merge "Enable H405 PEP8 check"