fixed locale of sub-requests when explicitely set by the developer (refs #8821)
added a functional test for locale handling in sub-requests
fixed request format when forwarding a request
merged branch fabpot/format-forward (PR #8829)

This PR was merged into the 2.2 branch.

Discussion
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fixed request format when forwarding a request

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #6932
| License       | MIT
| Doc PR        | n/a

When calling forward() in a controller, the format is not the same as for the master request.

Commits
-------

7e87eb1 fixed request format when forwarding a request
Merge branch '2.2' into 2.3

* 2.2:
  fixed request format when forwarding a request
  [HttpKernel] added a comment to warn about possible inconsistencies
  added a functional test for locale handling in sub-requests
  Fixed issue #6932 - Inconsistent locale handling in subrequests
  fixed locale of sub-requests when explicitely set by the developer (refs #8821)

Conflicts:
	src/Symfony/Component/HttpKernel/Tests/Fragment/InlineFragmentRendererTest.php