Ensure flake8 runs with a valid settings file
Ensure flake8 runs with a valid settings file

The H301 check sometimes imports a file when trying to tell whether it
is a module. Ensure we run flake8 in a valid environment to avoid
any side-effects from this.

Fixes bug #1191748.

Change-Id: I35fdefcd8f4c465a89f884299a0a9f4a4c79a6f6

tsufiev/horizon,Solinea/horizon,kfox1111/horizon,ging/horizon,wolverineav/horizon,yeming233/horizon,BiznetGIO/horizon,noironetworks/horizon,ging/horizon,kfox1111/horizon,damien-dg/horizon,gerrive/horizon,dan1/horizon-x509,henaras/horizon,ikargis/horizon_fod,BiznetGIO/horizon,spring-week-topos/horizon-week,saydulk/horizon,tqtran7/horizon,Dark-Hacker/horizon,j4/horizon,FNST-OpenStack/horizon,takeshineshiro/horizon,xme1226/horizon,flochaz/horizon,watonyweng/horizon,anthonydillon/horizon,tellesnobrega/horizon,tuskar/tuskar-ui,xme1226/horizon,spring-week-topos/horizon-week,noironetworks/horizon,mandeepdhami/horizon,redhat-openstack/horizon,pranavtendolkr/horizon,tanglei528/horizon,wangxiangyu/horizon,FNST-OpenStack/horizon,Dark-Hacker/horizon,nvoron23/avos,orbitfp7/horizon,aaronorosen/horizon-congress,gerrive/horizon,bac/horizon,tqtran7/horizon,flochaz/horizon,JioCloud/horizon,damien-dg/horizon,rickerc/horizon_audit,django-leonardo/horizon,NeCTAR-RC/horizon,henaras/horizon,yanheven/console,NCI-Cloud/horizon,ikargis/horizon_fod,xme1226/horizon,bigswitch/horizon,dan1/horizon-proto,promptworks/horizon,ikargis/horizon_fod,luhanhan/horizon,citrix-openstack-build/horizon,openstack/horizon,eayunstack/horizon,blueboxgroup/horizon,BiznetGIO/horizon,pranavtendolkr/horizon,j4/horizon,endorphinl/horizon,sandvine/horizon,pranavtendolkr/horizon,newrocknj/horizon,zouyapeng/horizon,icloudrnd/automation_tools,wolverineav/horizon,orbitfp7/horizon,philoniare/horizon,NCI-Cloud/horizon,mandeepdhami/horizon,wangxiangyu/horizon,nvoron23/avos,kfox1111/horizon,henaras/horizon,Hodorable/0602,redhat-openstack/horizon,mdavid/horizon,yjxtogo/horizon,promptworks/horizon,dan1/horizon-proto,openstack/horizon,yanheven/console,bac/horizon,maestro-hybrid-cloud/horizon,saydulk/horizon,watonyweng/horizon,tsufiev/horizon,CiscoSystems/avos,rickerc/horizon_audit,endorphinl/horizon-fork,takeshineshiro/horizon,JioCloud/horizon,Hodorable/0602,bigswitch/horizon,mandeepdhami/horizon,orbitfp7/horizon,Solinea/horizon,endorphinl/horizon,Daniex/horizon,xinwu/horizon,idjaw/horizon,RudoCris/horizon,CiscoSystems/horizon,karthik-suresh/horizon,rickerc/horizon_audit,Dark-Hacker/horizon,wangxiangyu/horizon,tuskar/tuskar-ui,rdo-management/tuskar-ui,gerrive/horizon,CiscoSystems/horizon,mrunge/openstack_horizon,davidcusatis/horizon,mrunge/horizon,RudoCris/horizon,NCI-Cloud/horizon,Tesora/tesora-horizon,openstack-ja/horizon,newrocknj/horizon,Mirantis/mos-horizon,NCI-Cloud/horizon,VaneCloud/horizon,VaneCloud/horizon,luhanhan/horizon,spring-week-topos/horizon-week,Solinea/horizon,mdavid/horizon,Tesora/tesora-horizon,openstack/horizon,yjxtogo/horizon,anthonydillon/horizon,ging/horizon,tanglei528/horizon,FNST-OpenStack/horizon,yeming233/horizon,gerrive/horizon,endorphinl/horizon-fork,mdavid/horizon,r-icarus/openstack_microserver,anthonydillon/horizon,luhanhan/horizon,NeCTAR-RC/horizon,tanglei528/horizon,ChameleonCloud/horizon,zouyapeng/horizon,agileblaze/OpenStackTwoFactorAuthentication,coreycb/horizon,aaronorosen/horizon-congress,vladryk/horizon,agileblaze/OpenStackTwoFactorAuthentication,noironetworks/horizon,redhat-openstack/horizon,watonyweng/horizon,dan1/horizon-x509,vladryk/horizon,redhat-cip/horizon,wangxiangyu/horizon,redhat-cip/horizon,django-leonardo/horizon,newrocknj/horizon,liyitest/rr,dan1/horizon-x509,mdavid/horizon,mrunge/horizon_lib,liyitest/rr,RudoCris/horizon,agileblaze/OpenStackTwoFactorAuthentication,RudoCris/horizon,yjxtogo/horizon,ging/horizon,izadorozhna/dashboard_integration_tests,philoniare/horizon,yeming233/horizon,tsufiev/horizon,CiscoSystems/avos,liyitest/rr,vladryk/horizon,tsufiev/horizon,blueboxgroup/horizon,promptworks/horizon,froyobin/horizon,newrocknj/horizon,liyitest/rr,VaneCloud/horizon,kaiweifan/horizon,gochist/horizon,tqtran7/horizon,mrunge/openstack_horizon,bac/horizon,nvoron23/avos,bac/horizon,eayunstack/horizon,blueboxgroup/horizon,aaronorosen/horizon-congress,Mirantis/mos-horizon,openstack-ja/horizon,blueboxgroup/horizon,rdo-management/tuskar-ui,Mirantis/mos-horizon,wolverineav/horizon,Tesora/tesora-horizon,BiznetGIO/horizon,Metaswitch/horizon,philoniare/horizon,idjaw/horizon,anthonydillon/horizon,r-icarus/openstack_microserver,j4/horizon,watonyweng/horizon,tellesnobrega/horizon,philoniare/horizon,coreycb/horizon,Metaswitch/horizon,tellesnobrega/horizon,openstack-ja/horizon,endorphinl/horizon,sandvine/horizon,sandvine/horizon,CiscoSystems/horizon,JioCloud/horizon,yjxtogo/horizon,xinwu/horizon,froyobin/horizon,karthik-suresh/horizon,saydulk/horizon,doug-fish/horizon,izadorozhna/dashboard_integration_tests,redhat-cip/horizon,luhanhan/horizon,dan1/horizon-proto,flochaz/horizon,xinwu/horizon,pranavtendolkr/horizon,karthik-suresh/horizon,endorphinl/horizon-fork,bigswitch/horizon,rdo-management/tuskar-ui,tellesnobrega/horizon,VaneCloud/horizon,karthik-suresh/horizon,rdo-management/tuskar-ui,mandeepdhami/horizon,Mirantis/mos-horizon,tuskar/tuskar-ui,mrunge/horizon,Metaswitch/horizon,zouyapeng/horizon,bigswitch/horizon,mrunge/horizon_lib,idjaw/horizon,yeming233/horizon,coreycb/horizon,kfox1111/horizon,noironetworks/horizon,zouyapeng/horizon,netscaler/horizon,sandvine/horizon,CiscoSystems/avos,r-icarus/openstack_microserver,citrix-openstack-build/horizon,kaiweifan/horizon,django-leonardo/horizon,vladryk/horizon,maestro-hybrid-cloud/horizon,yanheven/console,mrunge/horizon_lib,promptworks/horizon,dan1/horizon-proto,damien-dg/horizon,redhat-cip/horizon,FNST-OpenStack/horizon,doug-fish/horizon,davidcusatis/horizon,NeCTAR-RC/horizon,gochist/horizon,doug-fish/horizon,Hodorable/0602,gochist/horizon,agileblaze/OpenStackTwoFactorAuthentication,mrunge/horizon,CiscoSystems/horizon,davidcusatis/horizon,Solinea/horizon,mrunge/openstack_horizon,netscaler/horizon,xinwu/horizon,redhat-openstack/horizon,tqtran7/horizon,ChameleonCloud/horizon,citrix-openstack-build/horizon,ChameleonCloud/horizon,flochaz/horizon,j4/horizon,coreycb/horizon,NeCTAR-RC/horizon,kaiweifan/horizon,icloudrnd/automation_tools,doug-fish/horizon,Daniex/horizon,nvoron23/avos,maestro-hybrid-cloud/horizon,ChameleonCloud/horizon,Hodorable/0602,froyobin/horizon,davidcusatis/horizon,takeshineshiro/horizon,netscaler/horizon,endorphinl/horizon-fork,wolverineav/horizon,Metaswitch/horizon,icloudrnd/automation_tools,eayunstack/horizon,saydulk/horizon,takeshineshiro/horizon,henaras/horizon,damien-dg/horizon,orbitfp7/horizon,maestro-hybrid-cloud/horizon,idjaw/horizon,Tesora/tesora-horizon,dan1/horizon-x509,Daniex/horizon,CiscoSystems/avos,Daniex/horizon,icloudrnd/automation_tools,django-leonardo/horizon,openstack/horizon,Dark-Hacker/horizon,endorphinl/horizon