Fix Doctrine tests
[Tests] Make use of the @requires annotation for PHP version
merged branch vicb/test2 (PR #624)

This PR was merged into the master branch.

Commits
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8e11cfa [Tests] Make use of the @requires annotation for PHP version
1e0dd62 Fix Doctrine tests

Discussion
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[Test] Improvements

see https://github.com/fabpot/Silex/pull/620