bug #16086 fix validator test dependency (Tobion)

This PR was merged into the 3.0-dev branch.

Discussion
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fix validator test dependency

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

Fix test https://travis-ci.org/symfony/symfony/jobs/83308337#L3653 as property access is required for expression constraint.

Commits
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3b7cb33 fix validator test dependency

src/Symfony/Component/Validator/composer.json

@@ -25,6 +25,7 @@
         "symfony/intl": "~2.8|~3.0",
         "symfony/yaml": "~2.8|~3.0",
         "symfony/config": "~2.8|~3.0",
+        "symfony/property-access": "~2.8|~3.0",
         "symfony/expression-language": "~2.8|~3.0",
         "doctrine/annotations": "~1.0",
         "doctrine/cache": "~1.0",