fix dovecot restart

OTcerts.py

@@ -335,5 +335,5 @@ if __name__ == '__main__':
         # restart dovecot
         logger.info("Restarting dovecot")
         # ret = subprocess.run("systemctl restart dovecot")
-        ret = os.system("systemctl reload dovecot")
+        ret = os.system("systemctl restart dovecot")
         logger.info(ret)