Fix unit tests

PHPUnit 4.0.17 by Sebastian Bergmann.

Configuration read from /home/fox/src/php/ezsystems/zetacomponents/Debug/phpunit.xml.dist

................................................................. 65 / 65 (100%)


Time: 687 ms, Memory: 6.00Mb

OK (65 tests, 192 assertions)

Because this is what is defined here : https://github.com/zetacomponents/Debug/blob/master/tests/debug_message_test.php#L54