Fix remaining PEP8 (E***) and PyFlakes (F***) issues

E502 the backslash is redundant between brackets
E501 line too long (XX > 79 characters)
F841 local variable 'XXX' is assigned to but never used

Remove F403 and F999 from ignore list because there is
no violations related to these.

The remaining are all from OpenStack Hacking (H***) rules.

A part of blueprint openstack-hacking-compliant

Change-Id: I0fb46309621c15dfe4363039bbe46669f1315dec
Merge "Fix remaining PEP8 (E***) and PyFlakes (F***) issues"