Add tests dir to pep8 command
Add tests dir to pep8 command

Change-Id: I28120c67e157277202976696eea37023fb719d6d

openstack/python-glanceclient,mmasaki/python-glanceclient,mmasaki/python-glanceclient,ntt-sic/python-glanceclient,citrix-openstack-build/python-glanceclient,klmitch/python-glanceclient,JioCloud/python-glanceclient,openstack/python-glanceclient,alexpilotti/python-glanceclient,citrix-openstack-build/python-glanceclient,alexpilotti/python-glanceclient,klmitch/python-glanceclient,metacloud/python-glanceclient,varunarya10/python-glanceclient,metacloud/python-glanceclient,varunarya10/python-glanceclient,ntt-sic/python-glanceclient,JioCloud/python-glanceclient