Description:
------------
when setting a memcache value, and you specify an expiration time, the 
module appears to "double" serialize the value, so when you retrieve it 
later, it's still in a serialized string format.

Reproduce code:
---------------
<?php

$memc = memcache_pconnect("localhost",11211);
$values = array(1,2,3,4,5,6,7,8,9);
echo "Values: \n";
print_r($values);
echo "\n------------------------------\n";

$memc->set("myVals",$values,100);
$newValues = $memc->get("myVals");

echo"New Values:\n";
print_r($newValues);
echo "\n";

?>

Expected result:
----------------
Values: 
Array
(
    [0] => 1
    [1] => 2
    [2] => 3
    [3] => 4
    [4] => 5
    [5] => 6
    [6] => 7
    [7] => 8
    [8] => 9
)

------------------------------
New Values:
Array
(
    [0] => 1
    [1] => 2
    [2] => 3
    [3] => 4
    [4] => 5
    [5] => 6
    [6] => 7
    [7] => 8
    [8] => 9
)

Actual result:
--------------
Values: 
Array
(
    [0] => 1
    [1] => 2
    [2] => 3
    [3] => 4
    [4] => 5
    [5] => 6
    [6] => 7
    [7] => 8
    [8] => 9
)

------------------------------
New Values:
a:9:{i:0;i:1;i:1;i:2;i:2;i:3;i:3;i:4;i:4;i:5;i:5;i:6;i:6;i:7;i:7;i:8;i:8;i:9;}