Zabbix

...G...... [ZBX-17550] fixed agent2 log level check in case of DebugLevel=0

* commit '7c07359206255e8c762be2044a4344fd6f036815':
  ...G...... [ZBX-17550] fixed coding style
  ...G...... [ZBX-17550] changed log level Empty to None
  ...G...... [ZBX-17550] refactoring of logLevel
  ...G...... [ZBX-17550] fixed log level check in case of DebugLevel=0

(cherry picked from commit d50f1c353d4bd9b988a84194b23c78880d8d65d1)