[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 | -
There is no need to pass a writable stream. Locking in a distributed environment is totally different and need much more powerful tools (like http://www.consul.io/, very good tool).
So here, we use a file with `flock` system primitive.