xwm: update override-redirect surface's position upon configure_notify

When we receive configure_notify we should update the surface's
position by calling xwayland_api->set_xwayland(). Otherwise some surfaces
like dnd surfaces from xwayland views are "stuck" at one place. When
setting XWAYLAND state though we should always call view_set_position(),
not just the first time we set this state.

Signed-off-by: Ilia Bozhinov <ammen99@gmail.com>
Reviewed-by: Quentin Glidic <sardemff7+git@sardemff7.net>
diff --git a/libweston-desktop/xwayland.c b/libweston-desktop/xwayland.c
index 4f4b453..002e252 100644
--- a/libweston-desktop/xwayland.c
+++ b/libweston-desktop/xwayland.c
@@ -112,7 +112,6 @@
 				weston_desktop_surface_create_view(surface->surface);
 			weston_layer_entry_insert(&surface->xwayland->layer.view_list,
 						  &surface->view->layer_link);
-			weston_view_set_position(surface->view, x, y);
 			surface->view->is_mapped = true;
 			wsurface->is_mapped = true;
 		}
@@ -316,6 +315,7 @@
 {
 	weston_desktop_xwayland_surface_change_state(surface, XWAYLAND, NULL,
 						     x, y);
+	weston_view_set_position(surface->view, x, y);
 }
 
 static int