Qt4: fix m3u8 export extension

(cherry picked from commit 659bba5c453ae63ecb36bc8df3918eaa6113ae6c)

Conflicts:

	modules/gui/qt4/dialogs_provider.cpp

modules/gui/qt4/dialogs_provider.cpp

@@ -556,7 +556,7 @@ 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", },
     };