minor symfony#13159 Update functional tests to use the PSR NullLogger (stof)

This PR was merged into the 2.3 branch.

Discussion
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Update functional tests to use the PSR NullLogger

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

This avoids using the deprecated NullLogger in tests.

I'm applying this in 2.3 to make merging branches easier. This is especially needed for 2.7 because of deprecation warnings added in symfony#13060 (tests are failing in this PR currently because of that)

Commits
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30cff26 Update functional tests to use the PSR NullLogger

Author: fabpot

src/Symfony/Bundle/FrameworkBundle/Tests/Functional/app/config/framework.yml

@@ -11,4 +11,4 @@ framework:
         storage_id:     session.storage.mock_file
 
 services:
-    logger: { class: Symfony\Component\HttpKernel\Log\NullLogger }
+    logger: { class: Psr\Log\NullLogger }

src/Symfony/Bundle/SecurityBundle/Tests/Functional/app/FirewallEntryPoint/config.yml

@@ -12,7 +12,7 @@ framework:
     profiler: { only_exceptions: false }
 
 services:
-    logger: { class: Symfony\Component\HttpKernel\Log\NullLogger }
+    logger: { class: Psr\Log\NullLogger }
 
 security:
     firewalls:

src/Symfony/Bundle/SecurityBundle/Tests/Functional/app/config/framework.yml

@@ -12,4 +12,4 @@ framework:
     profiler: { only_exceptions: false }
 
 services:
-    logger: { class: Symfony\Component\HttpKernel\Log\NullLogger }
+    logger: { class: Psr\Log\NullLogger }