Fixed version requirements.

See:

 * https://bugs.php.net/bug.php?id=66021
 * php/php-src@82a4f1a
Missing parentheses.
https://bugs.php.net/bug.php?id=66021 has not been ported to HHVM yet.
Merge branch '4.0' into 4.1
Merge branch '4.1' into 4.2