[mutter] frames: use correct variable in for loop assignment

[Florian Müllner <fmuellner src gnome org>]

commit 3a374a6db55218462e423f1c9eedf9cae99fd093
Author: Shantanu Goel <sgoel01 yahoo com>
Date:   Sat Mar 18 21:10:45 2017 -0400

    frames: use correct variable in for loop assignment
    
    update_context_styles is using the wrong variable when advancing
    to the next key in the hash table which can cause an infinite
    loop if # of variants is ever greater than 1.
    
    This problem was originally reported here:
    
    https://github.com/linuxmint/Cinnamon/issues/5254
    
    The following patch was commited in Mint:
    
    https://github.com/linuxmint/muffin/commit/6120bdde
    
    This patch is just a shorter version of the Mint patch
    and they deserve all the credit for the idea.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=780254

 src/ui/frames.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/ui/frames.c b/src/ui/frames.c
index 271ed6b..2d86254 100644
--- a/src/ui/frames.c
+++ b/src/ui/frames.c
@@ -181,7 +181,7 @@ update_style_contexts (MetaFrames *frames)
   frames->normal_style = meta_theme_create_style_info (screen, NULL);
 
   variants = g_hash_table_get_keys (frames->style_variants);
-  for (variant = variants; variant; variant = variants->next)
+  for (variant = variants; variant; variant = variant->next)
     {
       style_info = meta_theme_create_style_info (screen, (char *)variant->data);
       g_hash_table_insert (frames->style_variants,