[gnome-builder] vala: fix function metadata

[Christian Hergert <chergert src gnome org>]

commit 2f86a09b4ddcf0a490f2df2ccc9687ab4c2df064
Author: Christian Hergert <chergert redhat com>
Date:   Mon Mar 11 16:51:21 2019 -0700

    vala: fix function metadata
    
    These are from tintou's branch working on out-of-process vala.

 src/Ide.metadata.in | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/src/Ide.metadata.in b/src/Ide.metadata.in
index f056f125d..dab7f9875 100644
--- a/src/Ide.metadata.in
+++ b/src/Ide.metadata.in
@@ -1,2 +1,4 @@
 *.ref unowned
 Task.new.callback type="GLib.TaskReadyCallback" scope="async"
+Object.parent_set.parent nullable=true
+Diagnostics.take.diagnostic owned=true