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.

pkg/madmin/examples/lock-list.go

@@ -1,46 +0,0 @@
-// +build ignore
-
-/*
- * Minio Cloud Storage, (C) 2016 Minio, Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-package main
-
-import (
-	"log"
-	"time"
-
-	"github.com/minio/minio/pkg/madmin"
-)
-
-func main() {
-	// Note: YOUR-ACCESSKEYID, YOUR-SECRETACCESSKEY are
-	// dummy values, please replace them with original values.
-
-	// API requests are secure (HTTPS) if secure=true and insecure (HTTPS) otherwise.
-	// New returns an Minio Admin client object.
-	madmClnt, err := madmin.New("your-minio.example.com:9000", "YOUR-ACCESSKEYID", "YOUR-SECRETACCESSKEY", true)
-	if err != nil {
-		log.Fatalln(err)
-	}
-
-	// List locks held on mybucket/myprefix for longer than 30s.
-	locksHeld, err := madmClnt.ListLocks("mybucket", "myprefix", time.Duration(30*time.Second))
-	if err != nil {
-		log.Fatalln(err)
-	}
-	log.Println(locksHeld)
-}