d3d11videosink: errors when reconfiguring caps

@seungha.yang : see this project, d3d11 branch, for a reproducer.

The errors are:

0:00:03.342104000  2412   03123780 ERROR            d3d11device gstd3d11device.c:717:gst_d3d11_device_create_swap_chain_internal:<d3d11device0> Cannot create SwapChain Object: 0x80070005
0:00:03.366167000  2412   03123848 ERROR            d3d11window gstd3d11window.c:994:gst_d3d11_window_prepare:<d3d11window0> Cannot create swapchain
0:00:03.376322000  2412   03123848 ERROR         d3d11videosink gstd3d11videosink.c:345:gst_d3d11_video_sink_set_caps:<d3d11videosink0> cannot create swapchain
Debug: Failed to prepare d3d11window
0:00:03.390473000  2412   03123780 ERROR            d3d11device gstd3d11device.c:717:gst_d3d11_device_create_swap_chain_internal:<d3d11device0> Cannot create SwapChain Object: 0x80070005
0:00:03.398254000  2412   03123848 ERROR            d3d11window gstd3d11window.c:994:gst_d3d11_window_prepare:<d3d11window0> Cannot create swapchain
0:00:03.405329000  2412   03123848 ERROR         d3d11videosink gstd3d11videosink.c:345:gst_d3d11_video_sink_set_caps:<d3d11videosink0> cannot create swapchain
Debug: Failed to prepare d3d11window
0:00:03.421279000  2412   03123780 ERROR            d3d11device gstd3d11device.c:717:gst_d3d11_device_create_swap_chain_internal:<d3d11device0> Cannot create SwapChain Object: 0x80070005
0:00:03.429357000  2412   03123848 ERROR            d3d11window gstd3d11window.c:994:gst_d3d11_window_prepare:<d3d11window0> Cannot create swapchain
0:00:03.436211000  2412   03123848 ERROR         d3d11videosink gstd3d11videosink.c:345:gst_d3d11_video_sink_set_caps:<d3d11videosink0> cannot create swapchain
Debug: Failed to prepare d3d11window
``