[libdazzle] multi-paned: fix horizontal layout bug

[Christian Hergert <chergert src gnome org>]

commit 98541e1fa2a6a459b7ce4a64c4f48a8b47dd0108
Author: Christian Hergert <chergert redhat com>
Date:   Wed Jun 21 16:45:31 2017 -0700

    multi-paned: fix horizontal layout bug
    
    We were adjusting height, not width when distributing out the extra space.
    This caused some funky rendering when in horizontal that did not show up
    in our vertical test case.

 src/widgets/dzl-multi-paned.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/widgets/dzl-multi-paned.c b/src/widgets/dzl-multi-paned.c
index b59c61e..4a7f56b 100644
--- a/src/widgets/dzl-multi-paned.c
+++ b/src/widgets/dzl-multi-paned.c
@@ -1273,7 +1273,7 @@ allocation_stage_expand (DzlMultiPaned   *self,
               if (gtk_widget_get_hexpand (child->widget))
                 {
                   child->alloc.width += adjust;
-                  state->avail_height -= adjust;
+                  state->avail_width -= adjust;
                   x_adjust += adjust;
                 }
             }