Add support for use of Erasure Coded pools with the Ceph RADOS Gateway.
Only the data pool is actually Erasure Coded - all other pools continue
to be replicated but have much smaller data footprints.
Depends-On: Iec4de19f7b39f0b08158d96c5cc1561b40aefa10
Change-Id: I661639e67853ff471a7d7ddea0e3fc2fcb30fed1