Lock DoctrineBundle to 1.5.2

Because of a bad change, SQLite database cannot be created anymore.

➡️ https://github.com/doctrine/DoctrineBundle/pull/434

composer.json

@@ -31,7 +31,7 @@
         "php": ">=5.3.3",
         "symfony/symfony": "~2.7.0",
         "doctrine/orm": "~2.3",
-        "doctrine/doctrine-bundle": "~1.2",
+        "doctrine/doctrine-bundle": "1.5.2",
         "twig/extensions": "~1.0",
         "symfony/assetic-bundle": "~2.3",
         "symfony/swiftmailer-bundle": "~2.3",