sync_music: Create destination directory

Create the destination directory when reading the settings. This
improves usability as the user doesn't have to enter a destination
directory that fully exists.

If there are no input files or if program aborts due to any reason
the created directory stays empty on the disk and is not deleted.

sync_music/sync_music.py

@@ -282,6 +282,9 @@ def load_settings(arguments=None):
         if settings.playlist_src is not None:
             paths.append('playlist_src')
         settings_dict = vars(settings)
+        if settings_dict['audio_dest']:
+            util.ensure_directory_exists(
+                util.makepath(settings_dict['audio_dest']))
         for path in paths:
             settings_dict[path] = util.makepath(settings_dict[path])
             if not os.path.isdir(settings_dict[path]):