Update zake to requirements version

Zake has been updated in the global requirements
repository to be zake>=0.0.20, so in order for the
requirements bot to get its change through (without
updating hacking) we need to separate this change
out.

Change-Id: I5cf4407104409785fe4ee746af9fed7b766474e4
Upgrade hacking version and fix some of the issues

Update hacking to the new requirements version and
fix about half of the new reported issues. The other
hacking issues are for now ignored until fixed by
adjusting our tox.ini file.

This commit fixes the following new hacking errors:

H405 - multi line docstring summary not separated
       with an empty line
E265 - block comment should start with '# '
F402 - import 'endpoint' from line 21 shadowed by
       loop variable

Change-Id: I6bae61591fb988cc17fa79e21cb5f1508d22781c
Adjust sphinx requirement

Bump up the sphinx requirement to match the
openstack requirements version to ensure
consistency among projects.

Change-Id: Ia348566c1c22ca31fa1cbdeb38d902ca0f622378
Merge "Update zake to requirements version"
Merge "Adjust sphinx requirement"
Merge "Upgrade hacking version and fix some of the issues"