Fix rendering of view when moving to new workspace

This is a possible fix for #384.

To be honest I don't fully understand why this bug is happening, but I
have narrowed it down to the view stack in wlc and how sway orders views
in very specific situations (those described in #384).

Anyway this should fix the problem by eliminating the call to
`wlc_view_bring_to_front` which isn't really needed anyway since sending
all invisible views to the back is the same as bringing all visible
views to the front (rotating the view stack).

sway/container.c

@@ -721,9 +721,7 @@ void update_visibility_output(swayc_t *container, wlc_handle output) {
 	if (container->type == C_VIEW) {
 		wlc_view_set_output(container->handle, output);
 		wlc_view_set_mask(container->handle, container->visible ? VISIBLE : 0);
-		if (container->visible) {
+		if (!container->visible) {
-			wlc_view_bring_to_front(container->handle);
-		} else {
 			wlc_view_send_to_back(container->handle);
 		}
 	}