Enable hacking H301 check

This commit enables the H301 hacking rule by removing all the
multiple imports in a single line from neutron.

Partial-Bug: #1291032

Change-Id: I7ba7f82fb36a433d73190eb3d568b6961ccb57c6
Fixing Arista CLI command

A minor change is made to the Arista API between ML2 Driver and the
back-end. This fix addresses this change to align Icehouse release with
Arista EOS releases.

Change-Id: Ia7cd3701c76d920a7e0d1334290c73ce7e8e5576
Closes-Bug: 1301093
update doc string - correct typo

Change-Id: I70503293cdd17a520dd9ec66ee297f2d36added6
Merge "update doc string - correct typo"
Merge "Fixing Arista CLI command"
Merge "Enable hacking H301 check"