e_hwc_window_queue: set backup buffer if user of queue is mismatched in buffer_change

e_hwc_window_queue: set backup buffer if user of queue is mismatched in buffer_change

it is possible that hwc_window has queue and queue buffer but queue of user is null.

hwc_window set queue and queue state is set ->
hwc_window unset queue and queue state is unset waiting ->
hwc_window set same queue and commit queue buffer ->
not set backup buffer

in this case, set backup buffer and should not be migrate HWC

Change-Id: I33b4324733733932db32be71179d5d7c069feac8