[vte] spawn: async: Release reference to VteTerminal

[Christian Persch <chpe src gnome org>]

commit 8ad57f190f33c41b1bc9051e919844a294feada9
Author: Christian Persch <chpe src gnome org>
Date:   Tue Mar 28 22:51:45 2017 +0200

    spawn: async: Release reference to VteTerminal
    
    https://bugzilla.gnome.org/show_bug.cgi?id=780663

 src/vtegtk.cc |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/src/vtegtk.cc b/src/vtegtk.cc
index 21282e1..f502d94 100644
--- a/src/vtegtk.cc
+++ b/src/vtegtk.cc
@@ -2361,6 +2361,8 @@ spawn_async_cb (GObject *source,
                 g_error_free(error);
 
         spawn_async_callback_data_free(data);
+
+        g_object_unref(terminal);
 }