Fix getEncryption() issue for multiple client.

This is a workaround for [getEncryption() issue #5](https://github.com/hoaproject/Socket/issues/5)

I know is maybe not the best way, but after lot review I don't find how implement that otherwise.
That can be a good beginning for work on best way.

Best Regards.
```php
if(true === $this->isEncrypted())
```