move flake8 option from run_tests.sh to tox.ini

[Kui Shi]

In run_tests.sh, the function run_flake8() still keep the flake8 option. They should be moved to the section [flake8] to tox.ini, and keep the function run_flake8() simple.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/42766

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/42766
Committed: http://github.com/openstack/keystone/commit/361185c0beb63a94288b6abc748c9163442f2c82
Submitter: Jenkins
Branch: master

commit 361185c0beb63a94288b6abc748c9163442f2c82
Author: Kui Shi <email address hidden>
Date: Tue Aug 20 06:28:04 2013 +0800

    remove flake8 option from run_tests.sh

    flake8 will read the section [flake8] of tox.ini to guide the
    behavior. In run_tests.sh, the function run_flake8() does not
    need the falke8 option any more.

    Fixes Bug #1214159
    Change-Id: I1bbba279a339e35c776a6969598b398f57fd7646