From the S3 layer after PutObject we were calling GetObjectInfo for bucket notification. This can
be avoided if PutObjectInfo returns ObjectInfo.
fixes#2567
This change initializes rpc servers associated with disks that are
local. It makes object layer initialization on demand, namely on the
first request to the object layer.
Also adds lock RPC service vendorized minio/dsync
Fixes a deadlock reproduced while running s3verify during
RemoveObject(). Previously held lock by GetObject() inside
the go-routine was never relenquished.