[polari] ui: Fix handler name

[Florian Müllner <fmuellner src gnome org>]

commit d3c11f0c3d02ce16ed56fbe51decae37736b2d30
Author: Florian Müllner <fmuellner gnome org>
Date:   Fri Jun 15 23:53:06 2018 +0200

    ui: Fix handler name
    
    https://gitlab.gnome.org/GNOME/polari/merge_requests/48

 data/resources/main-window.ui | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/data/resources/main-window.ui b/data/resources/main-window.ui
index 4056ce8..9247e48 100644
--- a/data/resources/main-window.ui
+++ b/data/resources/main-window.ui
@@ -15,7 +15,7 @@
     <property name="secondary-text" translatable="yes">Polari will continue to run when closed and will be 
automatically started on login.</property>
     <property name="destroy-with-parent">true</property>
     <property name="modal">true</property>
-    <signal name="delete-event" handler="gtk_widget_hide_on_delete"/>
+    <signal name="delete-event" handler="hide_on_delete"/>
     <child type="action">
       <object class="GtkButton" id="quitButton">
         <property name="label" translatable="yes">_Quit</property>