Remove  N342 from pep8 ignore list
Remove  N342 from pep8 ignore list

Current N342 is the nova check for central conf files.
[N342] Config options should be in the central location nova/conf/
We can just remove it from the ignore list. Hopefully, future rule
will be added in neutron-lib for such check in networking project.

Change-Id: Ib4d3eadeb100ea26f7ccfeaca14a219c29e43c2e
Partial-Bug: #1663864

openstack/dragonflow,openstack/dragonflow,openstack/dragonflow