AUP3: Remove obsolete audio file cache

src/ProjectAudioManager.cpp

@@ -916,9 +916,6 @@ You are saving directly to a slow external storage device\n\
          history.PushState(XO("Recorded Audio"), XO("Record"));
    }
 
-   // Write all cached files to disk, if any
-   dirManager.WriteCacheToDisk();
-
    // Now we auto-save again to get the project to a "normal" state again.
    projectFileIO.AutoSave();
 }
@@ -1170,4 +1167,4 @@ GetPropertiesOfSelected(const AudacityProject &proj)
    result.rateOfSelected = rateOfSelection;
 
    return  result;
-}
+}