[gnome-builder] meson: fix warning when restoring a project

[Christian Hergert <chergert src gnome org>]

commit cd79701011c803fec77739fc911ac781161680cf
Author: Christian Hergert <chergert redhat com>
Date:   Fri Feb 19 10:06:35 2021 -0800

    meson: fix warning when restoring a project

 src/plugins/meson/gbp-meson-build-system.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/plugins/meson/gbp-meson-build-system.c b/src/plugins/meson/gbp-meson-build-system.c
index bcdcb5423..bec4d92ef 100644
--- a/src/plugins/meson/gbp-meson-build-system.c
+++ b/src/plugins/meson/gbp-meson-build-system.c
@@ -294,7 +294,7 @@ gbp_meson_build_system_load_commands_async (GbpMesonBuildSystem *self,
    * here about whether or not it is setup fully. It may be delayed due
    * to device initialization.
    */
-  if (pipeline == NULL)
+  if (pipeline == NULL || !ide_pipeline_is_ready (pipeline))
     {
       ide_task_return_new_error (task,
                                  G_IO_ERROR,