[gnome-boxes] Non-void functions must return a value

[Zeeshan Ali Khattak <zeeshanak src gnome org>]

commit a4bc92cef82da1129c80ef6e2e98fed165977297
Author: Thomas Hindoe Paaboel Andersen <phomes gmail com>
Date:   Sat Feb 27 15:22:18 2016 +0100

    Non-void functions must return a value
    
    Correct return_if_fail() calls to return_val_if_fail() in a few boolean
    returning functions.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=762773

 src/app-window.vala |    2 +-
 src/wizard.vala     |    6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/src/app-window.vala b/src/app-window.vala
index e758c10..2e52a23 100644
--- a/src/app-window.vala
+++ b/src/app-window.vala
@@ -428,7 +428,7 @@ private class Boxes.AppWindow: Gtk.ApplicationWindow, Boxes.UI {
 
     [GtkCallback]
     private bool on_delete_event () {
-        return_if_fail (current_item == null || current_item is Machine);
+        return_val_if_fail (current_item == null || current_item is Machine, false);
 
         if (current_item != null) {
             var machine = current_item as Machine;
diff --git a/src/wizard.vala b/src/wizard.vala
index 13bf098..b579579 100644
--- a/src/wizard.vala
+++ b/src/wizard.vala
@@ -210,7 +210,7 @@ private class Boxes.Wizard: Gtk.Stack, Boxes.UI {
 
     public async bool review () {
         // only one outstanding review () permitted
-        return_if_fail (review_cancellable == null);
+        return_val_if_fail (review_cancellable == null, false);
 
         review_cancellable = new Cancellable ();
         var result = yield do_review_cancellable ();
@@ -428,7 +428,7 @@ private class Boxes.Wizard: Gtk.Stack, Boxes.UI {
         if (source != null || wizard_source.libvirt_sys_import)
             return true;
 
-        return_if_fail (vm_creator != null);
+        return_val_if_fail (vm_creator != null, false);
 
         vm_creator.install_media.bind_property ("ready-to-create",
                                                 continue_button, "sensitive",
@@ -443,7 +443,7 @@ private class Boxes.Wizard: Gtk.Stack, Boxes.UI {
     }
 
     private async bool do_review_cancellable () {
-        return_if_fail (review_cancellable != null);
+        return_val_if_fail (review_cancellable != null, false);
 
         nokvm_infobar.hide ();
         summary.clear ();