[gnome-builder] io: fix invalid check in write_async()

[Christian Hergert <chergert src gnome org>]

commit ecec03f3ec011219eced44b2fcbc4e289cf0e069
Author: Christian Hergert <chergert redhat com>
Date:   Fri Feb 1 20:32:59 2019 -0800

    io: fix invalid check in write_async()

 src/libide/io/ide-persistent-map-builder.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/libide/io/ide-persistent-map-builder.c b/src/libide/io/ide-persistent-map-builder.c
index 7556d87f3..8fc248ba9 100644
--- a/src/libide/io/ide-persistent-map-builder.c
+++ b/src/libide/io/ide-persistent-map-builder.c
@@ -291,7 +291,7 @@ ide_persistent_map_builder_write_async (IdePersistentMapBuilder *self,
   g_return_if_fail (G_IS_FILE (destination));
   g_return_if_fail (!cancellable || G_IS_CANCELLABLE (cancellable));
   g_return_if_fail (self->state != NULL);
-  g_return_if_fail (self->state->destination != NULL);
+  g_return_if_fail (self->state->destination == NULL);
 
   self->state->destination = g_object_ref (destination);