DVDnav: fix .ifo files opening

Should fix the issue mentionned on #3816, comment 14, 2 last results...

modules/demux/playlist/ifo.c

@@ -103,7 +103,11 @@ void Close_IFO( vlc_object_t *p_this )
 
 static int Demux( demux_t *p_demux )
 {
-    char *psz_url;
+    char *psz_url, *psz_dir;
+
+    psz_dir = strrchr( p_demux->psz_location, '/' );
+    if( psz_dir != NULL )
+       psz_dir[1] = '\0';
 
     if( asprintf( &psz_url, "dvd://%s", p_demux->psz_location ) == -1 )
         return 0;