Removed phpunit mock objects and MonologBundle dev deps

These are probably in there for test reasons in the past, but things
should work without them.

Author: wouterj

composer.json

@@ -22,8 +22,6 @@
         "symfony/phpunit-bridge": "^3.2",
         "matthiasnoback/symfony-dependency-injection-test": "~0.6",
         "matthiasnoback/symfony-config-test": "^1.3.1",
-        "phpunit/php-code-coverage": "@stable",
-        "symfony/monolog-bundle": "^2.3|^3.0",
         "doctrine/orm": "^2.5",
         "doctrine/data-fixtures": "^1.0.0"
     },