Description:
------------
If I unset an object property, after serialize/unserialize the property is re-initialized with default value defined in class declaration.

Reproduce code:
---------------
class test
{
    public $testUnset = 'default value';
}

$o = new test();
var_dump($o);

unset($o->testUnset);
var_dump($o);

$s = serialize($o);
$oo = unserialize($s);
var_dump($oo);

Expected result:
----------------
object(test)#1 (1) {
  ["testUnset"]=>
  string(13) "default value"
}
object(test)#1 (0) {
}
object(test)#2 (1) {
}

Actual result:
--------------
object(test)#1 (1) {
  ["testUnset"]=>
  string(13) "default value"
}
object(test)#1 (0) {
}
object(test)#2 (1) {
  ["testUnset"]=>
  string(13) "default value"
}