[gthumb] fixed compiler warning

[Paolo Bacchilega <paobac src gnome org>]

commit ce6f305627fb991ba838d865d80d3f6a9ebe2801
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Sat Apr 4 21:21:15 2015 +0200

    fixed compiler warning

 gthumb/gth-file-source-vfs.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gthumb/gth-file-source-vfs.c b/gthumb/gth-file-source-vfs.c
index fddf655..2ede8c9 100644
--- a/gthumb/gth-file-source-vfs.c
+++ b/gthumb/gth-file-source-vfs.c
@@ -772,7 +772,7 @@ gth_file_mananger_trash_files (GtkWindow *window,
        task = gth_trash_task_new (tdata->files);
        g_signal_connect (task,
                          "completed",
-                         trash_task_completed_cb,
+                         G_CALLBACK (trash_task_completed_cb),
                          tdata);
 
        gth_browser_exec_task (GTH_BROWSER (window), task, GTH_TASK_FLAGS_IGNORE_ERROR);