clients: add global_remove handler stubs

All the clients here were missing the global_remove handler. Because
window.c did not have it, weston-desktop-shell and weston-keyboard
segfaulted on compositor exit, as they received some
wl_registry.global_remove events.

Add more or less stub global_remove handlers, so that clients do not
crash on such events. Toytoolkit and all applications would need a lot
more code to properly handle the global object removal.

Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>
diff --git a/clients/simple-egl.c b/clients/simple-egl.c
index b84fae3..26ebe5c 100644
--- a/clients/simple-egl.c
+++ b/clients/simple-egl.c
@@ -588,8 +588,15 @@
 	}
 }
 
+static void
+registry_handle_global_remove(void *data, struct wl_registry *registry,
+			      uint32_t name)
+{
+}
+
 static const struct wl_registry_listener registry_listener = {
-	registry_handle_global
+	registry_handle_global,
+	registry_handle_global_remove
 };
 
 static void