This PR contains various fixes for the distributed release:
- Use DRWMutex in namespace-lock only for a single Lock()/RLock() call in conformance to server-side rw-locking as implemented in minio/dsync
- Implement missing cases in lock-rpc-server to catch Unlock() for active read locks and RUnlock() for an active write lock
- Refactor RPCClient to release local mutex while making actual RPC.Call()
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
Frank