Only invite to use -v if not already used

songbook

@@ -133,6 +133,7 @@ def main():
         sb_builder.build_steps(options.steps)
     except errors.SongbookError as error:
         LOGGER.error(error)
+        if LOGGER.level >= logging.INFO:
             LOGGER.error(
                     "Running again with option '-v' may give more information."
                     )