log_mhz19.py: add hashbang and make executable

diff --git a/log_mhz19.py b/log_mhz19.py
old mode 100644 (file)
new mode 100755 (executable)
index 57140d6..18ffb11
--- a/log_mhz19.py
+++ b/log_mhz19.py
@@ -1,3 +1,5 @@
+#!/usr/bin/python3
+
 import argparse
 import asyncio
 import logging