Change one overload of TieChoice to expect un-translated strings...

... preparatory to removing that overload.

This overload is used in exactly these files:

DevicePrefs.cpp (displaying host names retrieved by portaudio, which are not
defined in Audacity source)

EffectsPrefs.cpp

ExportFLAC.cpp (twice)

ExportMultiple.cpp (displaying the descriptions defined in the several export
plugin classes)

GUIPrefs.cpp (four times: languages, manual location, theme, and meter DB
range; the language names themselves don't have localizations!)

MidiIOPrefs.cpp (displaying host names retrieved by portmidi)

TracksBehaviorsPrefs.cpp (for solo button choices)

There is also TieNumberAsChoice, used in QualityPrefs and elsewhere, which
calls through to that overload.

src/export/ExportMP2.cpp

@@ -236,7 +236,7 @@ ExportMP2::ExportMP2()
    AddExtension(wxT("mp2"),0);
    SetMaxChannels(2,0);
    SetCanMetaData(true,0);
-   SetDescription(_("MP2 Files"),0);
+   SetDescription(XO("MP2 Files"),0);
 }
 
 ProgressResult ExportMP2::Export(AudacityProject *project,