Removed the global RC stability

As the RC version of the component is explicitly specified, specifying
it globally is useless. Moreover, this will prevents building using
RC version of other dependencies.

composer.json

@@ -24,8 +24,6 @@
         "matthiasnoback/symfony-config-test": "^1.3.1",
         "doctrine/phpcr-odm": "^1.3"
     },
-    "minimum-stability": "RC",
-    "prefer-stable": true,
     "suggest": {
         "doctrine/phpcr-odm": "To enable support for the PHPCR ODM documents",
         "doctrine/phpcr-bundle": "To enable support for the PHPCR ODM documents",