Remove reset to avoid passing by reference

[masakielastic]

I got the following warning when running examples/google.php.

PHP Strict Standards:  Only variables should be passed by reference 
in /Users/masakielastic/test/php-buzz-react/src/Message/Headers.php on line 39

I confirmed the bahavior of reset.

function test()
{
    return array('a', 'b', 'c');
}

var_dump(
    reset(test()),
    array_shift(test())
);

http://3v4l.org/CZi6i

[clue]

Awesome, thanks for spotting and providing the scripts to reproduce this! 👍

Interestingly, this wasn't reported by PHPUnit initially, despite using the convertNoticesToExceptions="true" configuration.

I've raised the default error reporting in tests/bootstrap.php and updated the test suite to cover this in the future (fdc9f31).