Define context.roles using base class
Define context.roles using base class

In Ia575ba803a0fb70f39146bd75d381ed19414bd23, oslo.context (2.2.0)
added roles support in the context itself. This passing roles to
super()__init__.

Depends-On: I74168f8aa7d4875b160e44ff53b9abd6083d1fe4
Change-Id: Idcf2acd020634881f0fd91d666fd0d0de56042de

klmitch/nova,Juniper/nova,vmturbo/nova,sebrandon1/nova,Juniper/nova,phenoxim/nova,bigswitch/nova,openstack/nova,rahulunair/nova,Juniper/nova,mahak/nova,zhimin711/nova,vmturbo/nova,klmitch/nova,rajalokan/nova,hanlind/nova,mahak/nova,cernops/nova,sebrandon1/nova,cloudbase/nova,gooddata/openstack-nova,rahulunair/nova,alaski/nova,jianghuaw/nova,cloudbase/nova,openstack/nova,openstack/nova,jianghuaw/nova,rajalokan/nova,hanlind/nova,vmturbo/nova,klmitch/nova,phenoxim/nova,rajalokan/nova,gooddata/openstack-nova,jianghuaw/nova,zhimin711/nova,cernops/nova,mahak/nova,cloudbase/nova,sebrandon1/nova,mikalstill/nova,rahulunair/nova,jianghuaw/nova,alaski/nova,gooddata/openstack-nova,mikalstill/nova,klmitch/nova,hanlind/nova,cernops/nova,vmturbo/nova,Juniper/nova,bigswitch/nova,mikalstill/nova,rajalokan/nova,gooddata/openstack-nova