[mutter] theme: Fix a memory leak

[Jasper St. Pierre <jstpierre src gnome org>]

commit 9b34545bd529ff8ab3c1ac3fbc4696f7ca32aad0
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Thu Jan 10 16:15:38 2013 -0500

    theme: Fix a memory leak
    
    Commit 5c33b0d tried to copy/paste the code that constructed
    classes, but for some reason didn't copy the theme name.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=690317

 src/ui/theme.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/src/ui/theme.c b/src/ui/theme.c
index e4516b3..f68fadc 100644
--- a/src/ui/theme.c
+++ b/src/ui/theme.c
@@ -5467,6 +5467,8 @@ meta_theme_create_style_context (GdkScreen   *screen,
                                       GTK_STYLE_PROVIDER_PRIORITY_SETTINGS);
     }
 
+  g_free (theme_name);
+
   return style;
 }