[gnome-font-viewer] Fix an uninitialized variable

[Matthias Clasen <matthiasc src gnome org>]

commit 9d4ec7300bbe57c2ebf36d292f6b574f27325fbc
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu Nov 13 14:25:09 2014 -0500

    Fix an uninitialized variable
    
    The str variable may be freed without ever having been set
    here, if we take one of the early gotos. This is showing up
    as a frequent crash in Fedoras retrace server:
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1148522

 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 3e76323..57be150 100644
--- a/src/font-thumbnailer.c
+++ b/src/font-thumbnailer.c
@@ -181,7 +181,7 @@ main (int argc,
     cairo_t *cr;
     cairo_text_extents_t text_extents;
     cairo_font_face_t *font;
-    gchar *str;
+    gchar *str = NULL;
     gdouble scale, scale_x, scale_y;
 
     const GOptionEntry options[] = {