[gnome-builder] xml: use g_clear_object

[Christian Hergert <chergert src gnome org>]

commit 4841c00eca5f68bb83a7fb65503d1fd2bd493f22
Author: Christian Hergert <chergert redhat com>
Date:   Wed Nov 22 00:24:05 2017 -0800

    xml: use g_clear_object

 src/plugins/xml-pack/ide-xml-completion-provider.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/src/plugins/xml-pack/ide-xml-completion-provider.c 
b/src/plugins/xml-pack/ide-xml-completion-provider.c
index c83ef2c..90ebeb0 100644
--- a/src/plugins/xml-pack/ide-xml-completion-provider.c
+++ b/src/plugins/xml-pack/ide-xml-completion-provider.c
@@ -99,10 +99,10 @@ populate_state_free (PopulateState *state)
 {
   g_assert (state != NULL);
 
-  g_object_unref (state->self);
-  g_object_unref (state->ifile);
-  g_object_unref (state->buffer);
-  g_object_unref (state->cancellable);
+  g_clear_object (&state->self);
+  g_clear_object (&state->ifile);
+  g_clear_object (&state->buffer);
+  g_clear_object (&state->cancellable);
   g_slice_free (PopulateState, state);
 }