[gnome-software/gnome-3-24] trivial: Fix leak of GCancellable

[Richard Hughes <rhughes src gnome org>]

commit 07bedf876aded6bb9984ae94c2648571ad4f1353
Author: Robert Ancell <robert ancell canonical com>
Date:   Tue Apr 4 15:31:15 2017 +1200

    trivial: Fix leak of GCancellable

 src/gs-updates-page.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/src/gs-updates-page.c b/src/gs-updates-page.c
index e9219bb..9489433 100644
--- a/src/gs-updates-page.c
+++ b/src/gs-updates-page.c
@@ -1399,6 +1399,10 @@ gs_updates_page_dispose (GObject *object)
                g_cancellable_cancel (self->cancellable_refresh);
                g_clear_object (&self->cancellable_refresh);
        }
+       if (self->cancellable_upgrade_download != NULL) {
+               g_cancellable_cancel (self->cancellable_upgrade_download);
+               g_clear_object (&self->cancellable_upgrade_download);
+       }
 
        g_clear_object (&self->builder);
        g_clear_object (&self->plugin_loader);