Fix condition for autoloader function definitions

[miromichalicka]

Since PHP 5.3.3 autoload functions can be also anonymous functions. This pull request fix problem for anonymous functions, as they are not in form of array.

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• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[magento-cicd2]

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