Remove broken --doctest call from run_pep8.sh
Remove broken --doctest call from run_pep8.sh

It does not seem to actually be required and causes the script to fail
when not running inside tox.

Change-Id: Ib5be301054b08623ea31a97c1b2d6c341e7fdd3e

pshchelo/heat,openstack/heat,rickerc/heat_audit,dragorosson/heat,rdo-management/heat,miguelgrinberg/heat,citrix-openstack-build/heat,steveb/heat,redhat-openstack/heat,redhat-openstack/heat,srznew/heat,pshchelo/heat,dims/heat,cryptickp/heat,pratikmallya/heat,maestro-hybrid-cloud/heat,ntt-sic/heat,jasondunsmore/heat,miguelgrinberg/heat,NeCTAR-RC/heat,JioCloud/heat,dims/heat,rh-s/heat,citrix-openstack-build/heat,openstack/heat,jasondunsmore/heat,NeCTAR-RC/heat,rickerc/heat_audit,rdo-management/heat,cwolferh/heat-scratch,takeshineshiro/heat,noironetworks/heat,ntt-sic/heat,srznew/heat,noironetworks/heat,cryptickp/heat,gonzolino/heat,rh-s/heat,steveb/heat,varunarya10/heat,maestro-hybrid-cloud/heat,takeshineshiro/heat,gonzolino/heat,varunarya10/heat,pratikmallya/heat,cwolferh/heat-scratch,dragorosson/heat,JioCloud/heat