Add support for timeouts for locks (#4377)

cmd/object-handlers-common.go

@@ -232,7 +232,9 @@ func isETagEqual(left, right string) bool {
 func deleteObject(obj ObjectLayer, bucket, object string, r *http.Request) (err error) {
 	// Acquire a write lock before deleting the object.
 	objectLock := globalNSMutex.NewNSLock(bucket, object)
-	objectLock.Lock()
+	if err = objectLock.GetLock(globalOperationTimeout); err != nil {
+		return err
+	}
 	defer objectLock.Unlock()
 
 	// Proceed to delete the object.