The current script is fragile to the introduction of a DEBUG logging
level. This change addresses the specifics of logging records being
returned when invoking the airflow command enough to make the dag_status
result end up being the last result as the script desires, so the script
is returned to working order, even if the logging level is set to DEBUG.
This change goes a little further to the point of removing all records
that indicate a logging level of DEBUG|INFO|WARN|ERROR.