update usage in run_test.sh for flake8
update usage in run_test.sh for flake8

Update usage info for pep8 options

Fixes bug #1210049

Change-Id: I8895550f204bd8b37d3c035221b7554761debf85

jonnary/keystone,blueboxgroup/keystone,dstanek/keystone,ntt-sic/keystone,reeshupatel/demo,JioCloud/keystone,reeshupatel/demo,jumpstarter-io/keystone,reeshupatel/demo,dstanek/keystone,ilay09/keystone,dstanek/keystone,roopali8/keystone,maestro-hybrid-cloud/keystone,rajalokan/keystone,promptworks/keystone,ging/keystone,jamielennox/keystone,maestro-hybrid-cloud/keystone,ilay09/keystone,UTSA-ICS/keystone-kerberos,openstack/keystone,ajayaa/keystone,nuxeh/keystone,derekchiang/keystone,promptworks/keystone,nuxeh/keystone,townbull/keystone-dtrust,roopali8/keystone,openstack/keystone,dims/keystone,dsiddharth/access-keys,rajalokan/keystone,idjaw/keystone,vivekdhayaal/keystone,cloudbau/keystone,cernops/keystone,cloudbau/keystone,rushiagr/keystone,dims/keystone,promptworks/keystone,jamielennox/keystone,blueboxgroup/keystone,ntt-sic/keystone,openstack/keystone,townbull/keystone-dtrust,rodrigods/keystone,mahak/keystone,UTSA-ICS/keystone-kerberos,citrix-openstack-build/keystone,rickerc/keystone_audit,ntt-sic/keystone,jonnary/keystone,derekchiang/keystone,townbull/keystone-dtrust,MaheshIBM/keystone,dsiddharth/access-keys,MaheshIBM/keystone,citrix-openstack-build/keystone,himanshu-setia/keystone,klmitch/keystone,rushiagr/keystone,cloudbau/keystone,nuxeh/keystone,derekchiang/keystone,rickerc/keystone_audit,JioCloud/keystone,mahak/keystone,citrix-openstack-build/keystone,ilay09/keystone,ajayaa/keystone,takeshineshiro/keystone,jumpstarter-io/keystone,mahak/keystone,rushiagr/keystone,vivekdhayaal/keystone,ging/keystone,klmitch/keystone,idjaw/keystone,rickerc/keystone_audit,cernops/keystone,jumpstarter-io/keystone,vivekdhayaal/keystone,rodrigods/keystone,dsiddharth/access-keys,takeshineshiro/keystone,rajalokan/keystone,himanshu-setia/keystone