[easytag] Use et_str_empty() in another place

[David King <davidk src gnome org>]

commit 7454529fa6b346237552d93d443e4821bc505b5a
Author: David King <amigadave amigadave com>
Date:   Thu Jan 14 18:27:02 2016 +0000

    Use et_str_empty() in another place

 src/application_window.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/application_window.c b/src/application_window.c
index 92da371..b7e2c6a 100644
--- a/src/application_window.c
+++ b/src/application_window.c
@@ -2035,7 +2035,7 @@ et_application_window_update_file_name_from_ui (EtApplicationWindow *self,
     //ET_File_Name_Check_Length(ETFile,filename);
 
     /* Filename (in file system encoding!). */
-    if (filename && *filename)
+    if (!et_str_empty (filename))
     {
         /* Regenerate the new filename (without path). */
         filename_new = g_strconcat (filename, extension, NULL);