Update Oslo wiki link in README
Update Oslo wiki link in README

Use latest Oslo wiki link.

Change-Id: I6cedf162d66f7b5e339282f3086fd67839d761db

rh-s/heat,dragorosson/heat,takeshineshiro/heat,miguelgrinberg/heat,takeshineshiro/heat,redhat-openstack/heat,jasondunsmore/heat,maestro-hybrid-cloud/heat,pshchelo/heat,noironetworks/heat,dragorosson/heat,srznew/heat,cryptickp/heat,pratikmallya/heat,cwolferh/heat-scratch,NeCTAR-RC/heat,steveb/heat,rh-s/heat,cwolferh/heat-scratch,openstack/heat,rdo-management/heat,gonzolino/heat,jasondunsmore/heat,miguelgrinberg/heat,NeCTAR-RC/heat,steveb/heat,noironetworks/heat,maestro-hybrid-cloud/heat,pshchelo/heat,pratikmallya/heat,redhat-openstack/heat,srznew/heat,openstack/heat,dims/heat,dims/heat,cryptickp/heat,gonzolino/heat,rdo-management/heat