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/xl-sets.go

@@ -1433,24 +1433,3 @@ func (s *xlSets) ListObjectsHeal(ctx context.Context, bucket, prefix, marker, de
 	// Return error at the end.
 	return loi, toObjectErr(err, bucket, prefix)
 }
-
-// ListLocks from all sets, aggregate them and return.
-func (s *xlSets) ListLocks(ctx context.Context, bucket, prefix string, duration time.Duration) (lockInfo []VolumeLockInfo, err error) {
-	for _, set := range s.sets {
-		var setLockInfo []VolumeLockInfo
-		setLockInfo, err = set.ListLocks(ctx, bucket, prefix, duration)
-		if err != nil {
-			return nil, err
-		}
-		lockInfo = append(lockInfo, setLockInfo...)
-	}
-	return lockInfo, nil
-}
-
-// Clear all requested locks on all sets.
-func (s *xlSets) ClearLocks(ctx context.Context, lockInfo []VolumeLockInfo) error {
-	for _, set := range s.sets {
-		set.ClearLocks(ctx, lockInfo)
-	}
-	return nil
-}