fixed the unit tests

Author: Alexandre Guidet

Migrate/Command/AddEnvCommand.php

@@ -7,7 +7,6 @@
 
 namespace Migrate\Command;
 
-use Symfony\Component\Config\Definition\Exception\Exception;
 use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Output\OutputInterface;
 use Symfony\Component\Console\Question\ChoiceQuestion;