Deprecate ListLocks and ClearLocks (#6233)

No locks are ever left in memory, we also
have a periodic interval of clearing stale locks
anyways. The lock instrumentation was not complete
and was seldom used.

Deprecate this for now and bring it back later if
it is really needed. This also in-turn seems to improve
performance slightly.

cmd/admin-rpc-server.go

@@ -19,7 +19,6 @@ package cmd
 import (
 	"context"
 	"path"
-	"time"
 
 	"github.com/gorilla/mux"
 	"github.com/minio/minio/cmd/logger"
@@ -47,20 +46,6 @@ func (receiver *adminRPCReceiver) SignalService(args *SignalServiceArgs, reply *
 	return receiver.local.SignalService(args.Sig)
 }
 
-// ListLocksQuery - wraps ListLocks API's query values to send over RPC.
-type ListLocksQuery struct {
-	AuthArgs
-	Bucket   string
-	Prefix   string
-	Duration time.Duration
-}
-
-// ListLocks - lists locks held by requests handled by this server instance.
-func (receiver *adminRPCReceiver) ListLocks(args *ListLocksQuery, reply *[]VolumeLockInfo) (err error) {
-	*reply, err = receiver.local.ListLocks(args.Bucket, args.Prefix, args.Duration)
-	return err
-}
-
 // ServerInfo - returns the server info when object layer was initialized on this server.
 func (receiver *adminRPCReceiver) ServerInfo(args *AuthArgs, reply *ServerInfoData) (err error) {
 	*reply, err = receiver.local.ServerInfo()