[pango] Fix warning in g_object_ref (NULL)

[Behdad Esfahbod <behdad src gnome org>]

commit 87ed96661e6217727f59fe372b47ff66ccbf578b
Author: Behdad Esfahbod <behdad behdad org>
Date:   Mon Jan 7 02:10:03 2013 -0600

    Fix warning in g_object_ref (NULL)

 pango/pangocairo-fontmap.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/pango/pangocairo-fontmap.c b/pango/pangocairo-fontmap.c
index 946ef41..8f3cc53 100644
--- a/pango/pangocairo-fontmap.c
+++ b/pango/pangocairo-fontmap.c
@@ -185,7 +185,10 @@ pango_cairo_font_map_set_default (PangoCairoFontMap *fontmap)
 {
   g_return_if_fail (fontmap == NULL || PANGO_IS_CAIRO_FONT_MAP (fontmap));
 
-  g_private_replace (&default_font_map, g_object_ref (fontmap));
+  if (fontmap)
+    g_object_ref (fontmap);
+
+  g_private_replace (&default_font_map, fontmap);
 }
 
 /**