Merge branch '2.7' into 2.8

Conflicts:
	src/Symfony/Component/Security/Http/Tests/RememberMe/PersistentTokenBasedRememberMeServicesTest.php
	src/Symfony/Component/Security/Http/Tests/RememberMe/TokenBasedRememberMeServicesTest.php
	src/Symfony/Component/Security/composer.json

Author: nicolas-grekas

Resources/config/debug_prod.xml

@@ -14,7 +14,7 @@
         <service id="debug.debug_handlers_listener" class="%debug.debug_handlers_listener.class%">
             <tag name="kernel.event_subscriber" />
             <tag name="monolog.logger" channel="php" />
-            <argument /><!-- Exception handler -->
+            <argument>null</argument><!-- Exception handler -->
             <argument type="service" id="logger" on-invalid="null" />
             <argument>null</argument><!-- Log levels map for enabled error levels -->
             <argument>null</argument>