Description:
------------
See:http://bugs.php.net/bug.php?id=26639

Although the usual array is satisfactory, 
if array becomes a nest, it is still useless.


Reproduce code:
---------------
<?
// no problem.
$Array1  = array( "multi-byte string's" );
$Array2  = $Array1;

mb_convert_variables( "SJIS",
                      mb_detect_order( ),
                      $Array2 );

var_dump( $Array1 );
var_dump( $Array2 );

// unexpected operation.
$Array1  = array( "multi-byte string's", array( "multi-byte string's" ) );
$Array2  = $Array1;

mb_convert_variables( "SJIS",
                      mb_detect_order( ),
                      $Array2 );

var_dump( $Array1 );
var_dump( $Array2 );
?>

Expected result:
----------------
array(1) {
  [0]=>
  string(3) "no changed multi-byte string's"
}

array(1) {
  [0]=>
  string(3) "changed multi-byte string's"
}

array(1) {
  [0]=>
  string(3) "no changed multi-byte string's"
  [1]=>
   array(1) {
     [0]=>
     string(4) "no changed multi-byte string's"
   }
}

array(1) {
  [0]=>
  string(3) "changed multi-byte string's"
  [1]=>
   array(1) {
     [0]=>
     string(4) "changed multi-byte string's"
   }
}


Actual result:
--------------
array(1) {
  [0]=>
  string(3) "no changed multi-byte string's"
}

array(1) {
  [0]=>
  string(3) "changed multi-byte string's"
}

array(1) {
  [0]=>
  string(3) "no changed multi-byte string's"
  [1]=>
   array(1) {
     [0]=>
     string(4) "changed  multi-byte string's"
   }
}

array(1) {
  [0]=>
  string(3) "changed multi-byte string's"
  [1]=>
   array(1) {
     [0]=>
     string(4) "changed multi-byte string's"
   }
}