[Command] Added LockHelper

| Q             | A
| ------------- | ---
| Doc fix?      | no
| New docs?     | yes https://github.com/symfony/symfony/pull/10475
| Applies to    | Symfony version 2.6+
| Fixed tickets | -
this seems to be missing something. I would simply replace all code in this if statement by `// the resource "hello" is already locked by another process`