Prevents error from array_shift in mobile theme

On PHP 5.4.24, the follow error is displayed when using the mobile theme:
`Strict Standards: Only variables should be passed by reference in /wp-content/plugins/jetpack/modules/minileven/theme/pub/minileven/header.php on line 33`

Reported in http://wordpress.org/support/topic/headerphp-call-by-reference-php-error-in-mobile-minileven-jetpack-theme