merged branch benja-M-1/patch-upgrade-2.2 (PR #6435)

This PR was merged into the master branch.

Commits
-------

4d40b11 Add notes about kernel.trusted_proxies parameter

Discussion
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[2.2][Upgrade] Add notes about kernel.trusted_proxies parameter

Bug fix: no
Feature addition: no
Backwards compatibility break: no
Symfony2 tests pass: yes
License of the code: MIT

The UPGRADE-2.2.md does not mention that we have to replace ```trust_proxy_headers``` with ```trusted_proxies```.

UPGRADE-2.2.md

@@ -362,3 +362,24 @@
    protected $gender;
    ```
 
+### FrameworkBundle
+
+#### Configuration
+
+ * The 2.2 version introduces a new parameter ```trusted_proxies``` that replaces ```trust_proxy_headers``` in the framework configuration.
+
+   Before:
+
+   ```
+   # app/config/config.yml
+   framework:
+       trust_proxy_headers: false
+   ```
+
+   After:
+
+   ```
+   # app/config/config.yml
+   framework:
+      trusted_proxies: []
+   ```