[mutter] frames: Make sure to initialize button_state

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

commit 0faa900207c46dc76726456d745202326bce5f5d
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Mon Sep 29 19:57:55 2014 -0600

    frames: Make sure to initialize button_state
    
    Otherwise, we're comparing with uninitialized memory. Spotted by
    valgrind.

 src/ui/frames.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/src/ui/frames.c b/src/ui/frames.c
index a2925ec..c1571f3 100644
--- a/src/ui/frames.c
+++ b/src/ui/frames.c
@@ -573,6 +573,7 @@ meta_frames_manage_window (MetaFrames *frames,
   frame->title = NULL;
   frame->shape_applied = FALSE;
   frame->prelit_control = META_FRAME_CONTROL_NONE;
+  frame->button_state = META_BUTTON_STATE_NORMAL;
 
   meta_core_grab_buttons (GDK_DISPLAY_XDISPLAY (gdk_display_get_default ()), frame->xwindow);