[#2565] Adding a note about the profiler.enabled key that was added in 2.2

Author: weaverryan

reference/configuration/framework.rst

@@ -39,6 +39,8 @@ Configuration
     * `assets_base_urls`_
     * `assets_version`_
     * `assets_version_format`_
+* `profiler`_
+    * `enabled`_
 
 secret
 ~~~~~~
@@ -397,6 +399,22 @@ would be ``/images/logo.png?version=5``.
     The latter option is useful if you would like older asset versions to remain
     accessible at their original URL.
 
+profiler
+~~~~~~~~
+
+.. versionadded:: 2.2
+    The ``enabled`` option was added in Symfony 2.2. Previously, the profiler
+    could only be disabled by omitting the ``framework.profiler`` configuration
+    entirely.
+
+enabled
+.......
+
+**default**: ``true`` in the ``dev`` and ``test`` environments
+
+The profiler can be disabled by setting this key to ``false``. In reality,
+the profiler still exists, but the data collectors are not activated.
+
 Full Default Configuration
 --------------------------