Add property doc strings for S3 bucket
Add property doc strings for S3 bucket

Change-Id: I508a6ea45748e366c4cc4f6f47f200ac4145cee1
Closes-bug: #1224148

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