Only detach children from a different client than parent.

The purpose of detach is prevent another client from modifying
the layer. Therefore, layers with the same client as their parent
shouldn't be detached because the parent can and should be able
to still modify those layers.

Test: Updated Transaction_test so it has a test when the parent detaches
children with same client and detaches children with different client.

Change-Id: Ieede3c7b472e6eaa567163876b71cc9d7e889daf