[easytag] Fix invalid read in rename file dialog

[David King <davidk src gnome org>]

commit b6707afd59697f96a4e43e69876c436cd15f6e91
Author: David King <amigadave amigadave com>
Date:   Sat May 4 14:02:15 2013 +0100

    Fix invalid read in rename file dialog
    
    Set the pointer to the preview label to NULL when destroying the dialog.

 src/browser.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/src/browser.c b/src/browser.c
index a8e6e05..ce97f24 100644
--- a/src/browser.c
+++ b/src/browser.c
@@ -3721,6 +3721,7 @@ Destroy_Rename_Directory_Window (void)
         gtk_list_store_clear(RenameDirectoryMaskModel);
 
         gtk_widget_destroy(RenameDirectoryWindow);
+        RenameDirectoryPreviewLabel = NULL;
         RenameDirectoryWindow = NULL;
     }
 }