Qt4: fix m3u8 export extension

modules/gui/qt4/dialogs_provider.cpp

@@ -559,7 +559,7 @@ void DialogsProvider::saveAPlaylist()
         char module[12];
     } types[] = {
         { N_("XSPF playlist"), "*.xspf", "export-xspf", },
-        { N_("M3U8 playlist"), "*.m3u", "export-m3u8", },
+        { N_("M3U8 playlist"), "*.m3u8", "export-m3u8", },
         { N_("M3U playlist"), "*.m3u", "export-m3u", },
         { N_("HTML playlist"), "*.html", "export-html", },
     };