[gvfs] Do not call NULL callbacks in eject_wrapper_callback()

[Ondrej Holy <oholy src gnome org>]

commit fcbf262537f3d14035ac31107c7a4ba7a31905af
Author: Siteshwar Vashisht <svashish redhat com>
Date:   Wed Jan 14 14:39:32 2015 +0530

    Do not call NULL callbacks in eject_wrapper_callback()

 monitor/proxy/gproxymount.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/monitor/proxy/gproxymount.c b/monitor/proxy/gproxymount.c
index 64e128d..73af376 100644
--- a/monitor/proxy/gproxymount.c
+++ b/monitor/proxy/gproxymount.c
@@ -386,7 +386,8 @@ eject_wrapper_callback (GObject *source_object,
                         gpointer user_data)
 {
   EjectWrapperOp *data  = user_data;
-  data->callback (data->object, res, data->user_data);
+  if (data->callback)
+    data->callback (data->object, res, data->user_data);
   g_object_unref (data->object);
   g_free (data);
 }