fix: improper ticker usage in goroutines (#11468)

- lock maintenance loop was incorrectly sleeping
  as well as using ticker badly, leading to
  extra expiration routines getting triggered
  that could flood the network.

- multipart upload cleanup should be based on
  timer instead of ticker, to ensure that long
  running jobs don't get triggered twice.

- make sure to get right lockers for object name

cmd/metacache-manager.go

@@ -64,6 +64,8 @@ func (m *metacacheManager) initManager() {
 		}
 
 		t := time.NewTicker(time.Minute)
+		defer t.Stop()
+
 		var exit bool
 		bg := context.Background()
 		for !exit {