libobs-d3d11: Fix bug where vertex buffers would be reset

There's no need to reset vertex buffers like this anymore.  This would
unintentionally cause certain things (such as the freetype text source
on windows) to stop rendering properly.

libobs-d3d11/d3d11-subsystem.cpp

@@ -1039,9 +1039,6 @@ void device_load_vertexshader(gs_device_t *device, gs_shader_t *vertshader)
 			return;
 		}
 
-		if (curVB)
-			device_load_vertexbuffer(device, NULL);
-
 		shader    = vs->shader;
 		layout    = vs->layout;
 		constants = vs->constants;