Have container sync get its object ring from POLICIES now,
update tests to use policy index from container_info and pass
that along for use in ring selection.
This change also introduced the option of specifiying in the cluster info
which of the relam/cluster's is the current realm/cluster.
DocImpact
Implements: blueprint storage-policies
Change-Id: If57d3b0ff8c395f21c81fda76458bc34fcb23257
6da9799917