[gnome-font-viewer] font-thumbnailer: fix GCC warning

[Cosimo Cecchi <cosimoc src gnome org>]

commit dcc436b7cdb08beb07144ee55d96f32b065d47f6
Author: Cosimo Cecchi <cosimoc gnome org>
Date:   Sat Nov 21 14:19:07 2015 -0800

    font-thumbnailer: fix GCC warning

 src/font-thumbnailer.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/font-thumbnailer.c b/src/font-thumbnailer.c
index 57be150..2c31acd 100644
--- a/src/font-thumbnailer.c
+++ b/src/font-thumbnailer.c
@@ -65,7 +65,7 @@ check_font_contain_text (FT_Face face,
   gunichar *string;
   glong len, idx, map;
   FT_CharMap charmap;
-  gboolean retval;
+  gboolean retval = FALSE;
 
   string = g_utf8_to_ucs4_fast (text, -1, &len);