compositor: Remove double free()s in resource destructors

With the change to move free()ing of the wl_resource into wayland-server, we now have
a few cases where we double free the resource in the destructor.  This patch
removes those.

src/compositor.c

@@ -2206,8 +2206,6 @@ subsurface_resource_destroy(struct wl_resource *resource)
 
 	if (sub)
 		weston_subsurface_destroy(sub);
-
-	free(resource);
 }
 
 static void

src/input.c

@@ -40,7 +40,6 @@ empty_region(pixman_region32_t *region)
 static void unbind_resource(struct wl_resource *resource)
 {
 	wl_list_remove(wl_resource_get_link(resource));
-	free(resource);
 }
 
 void

src/text-backend.c

@@ -533,8 +533,6 @@ unbind_keyboard(struct wl_resource *resource)
 
 	input_method_context_end_keyboard_grab(context);
 	context->keyboard = NULL;
-
-	free(resource);
 }
 
 static void
@@ -746,8 +744,6 @@ unbind_input_method(struct wl_resource *resource)
 	input_method->context = NULL;
 
 	text_backend->input_method.binding = NULL;
-
-	free(resource);
 }
 
 static void