create-sound-files: create parent directories if needed

emissions/management/commands/create-sound-files.py

@@ -82,7 +82,7 @@ class Command(BaseCommand):
     def create(self, soundfile, format):
         file_path = soundfile.get_format_path(format)
         if not os.path.exists(os.path.dirname(file_path)):
-            os.mkdir(os.path.dirname(file_path))
+            os.makedirs(os.path.dirname(file_path))
 
         if self.copy and os.path.splitext(soundfile.file.path)[-1].strip('.') == format:
             shutil.copy(soundfile.file.path, file_path)