libobs-d3d11: Make shared texture error message less vague

libobs-d3d11/d3d11-texture2d.cpp

@@ -191,7 +191,7 @@ gs_texture_2d::gs_texture_2d(gs_device_t *device, uint32_t handle)
 	hr = device->device->OpenSharedResource((HANDLE)(uintptr_t)handle,
 			__uuidof(ID3D11Texture2D), (void**)texture.Assign());
 	if (FAILED(hr))
-		throw HRError("Failed to open resource", hr);
+		throw HRError("Failed to open shared 2D texture", hr);
 
 	texture->GetDesc(&td);