Remove dogpile from heat requirements
Remove dogpile from heat requirements

oslo.caching has a dependency on dogpile cache. So we don't need
to have it in heat requirements anymore.

Change-Id: I2f700ae5dea960d75d1cef85541c0fa226dfd539

dragorosson/heat,steveb/heat,noironetworks/heat,dims/heat,jasondunsmore/heat,takeshineshiro/heat,cwolferh/heat-scratch,pratikmallya/heat,cryptickp/heat,steveb/heat,jasondunsmore/heat,srznew/heat,miguelgrinberg/heat,openstack/heat,pratikmallya/heat,noironetworks/heat,dragorosson/heat,openstack/heat,cryptickp/heat,maestro-hybrid-cloud/heat,miguelgrinberg/heat,maestro-hybrid-cloud/heat,gonzolino/heat,srznew/heat,gonzolino/heat,cwolferh/heat-scratch,takeshineshiro/heat,dims/heat