Remove unused option from ObjectReplicator.__init__

disk_chunk_size is unused by the ObjectReplicator class. Note that it
*is* used by the object replicator process; it's just that
DiskFileManager is the one that pulls it out of the conf and pays
attention to it. Keeping it as an attribute on ObjectReplicator is
unnecessary.

Change-Id: I1eeef7b33873b4c8bb269ca02dcb067098b6fded
use get_container_info in ratelimit

Everyone else cooperates to store the container_info cache in the env the
first time it's requested.  This should save a duplicate memcache hit on
requests that ratelimiting looks at.

Change-Id: Ic6411d4619db6b53fafe9fdbf1d0a370d1258c38
Merge "Remove unused option from ObjectReplicator.__init__"
Merge "use get_container_info in ratelimit"