[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 | -
What about changing this:

`... the PHP code will not be executed further unless the lock is released by another process.`

with this:

`... your PHP code will wait indefinitely until the lock is released by another process.`