Description:
------------
There is missing INIT_PZVAL(return_value);
at end of zif_func_get_arg thus it is leaking
data.

Reproduce code:
---------------
<?php
function f()
{
        echo func_get_arg(0);
}               
$a=$b=2;
f($a);
?>


Expected result:
----------------
2/copy/build/php-5.1.0RC1/Zend/zend_vm_execute.h(167) :  Freeing 0x08466324 (16 bytes), script=tst.php
=== Total 1 memory leaks detected ===

Actual result:
--------------
2