inconsistent private attribute handling

[frankli0324]

as shown in

libphpserialize/phpserialize/serialize.py

Lines 102 to 105 in 8c2d724

	# Limitation: this locks `attr_type` to current type,
	# so when private properties are inherited from
	# other classes, this may produce different output
	# with php itself.

consider a php object:

class A {
    private $a = 1;
}
class B extends A {
    private $a = 2;
}
new B();

php stores both a attributes, while with dir(), python returns all attributes, both declared or inherited, without distinguishing them.

so

class TestQwer:
    private_y = 1234
class TestNamespace(TestQwer):
    private_y = 2345
s = serialize(TestNamespace())

yields O:13:"TestNamespace":1:{s:16:"TestNamespacey";i:2345;} while the php code above yields O:1:"B":2:{s:4:"Ba";i:2;s:4:"Aa";i:1;}

object(__PHP_Incomplete_Class)#1 (3) {
  ["__PHP_Incomplete_Class_Name"]=>
  string(1) "B"
  ["a":"B":private]=>
  int(2)
  ["a":"A":private]=>
  int(1)
}