[gtk] reftests: Fix grid-spacing1 test

[Benjamin Otte <otte src gnome org>]

commit b3eddbb45dce968524c767f88bb609f5f2e2fe69
Author: Benjamin Otte <otte redhat com>
Date:   Wed Mar 27 03:46:03 2019 +0100

    reftests: Fix grid-spacing1 test

 testsuite/reftests/grid-spacing1.ref.ui | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/testsuite/reftests/grid-spacing1.ref.ui b/testsuite/reftests/grid-spacing1.ref.ui
index 0c3d574f5a..9e9ee1d5d8 100644
--- a/testsuite/reftests/grid-spacing1.ref.ui
+++ b/testsuite/reftests/grid-spacing1.ref.ui
@@ -80,6 +80,7 @@
               <object class="GtkLabel" id="b">
                 <property name="visible">True</property>
                 <property name="label">B</property>
+                <property name="hexpand">True</property>
               </object>
             </child>
             <child>