bot-status.py: Describe -d debug option

Change-Id: Id251681400ba80dccbcc19f6d5c0917512a3f339
diff --git a/monitor/bot-status.py b/monitor/bot-status.py
index 11e725f..b7d265d 100755
--- a/monitor/bot-status.py
+++ b/monitor/bot-status.py
@@ -218,7 +218,8 @@
 
 if __name__ == "__main__":
   parser = argparse.ArgumentParser()
-  parser.add_argument('-d', dest='debug', action='store_true')
+  parser.add_argument('-d', dest='debug', action='store_true',
+                      help='show debug log messages')
   parser.add_argument('config_file',
                       help='Bots description in JSON format')
   parser.add_argument('output_file',