int degree specifies the severity of the error. It must be one of the following constants:
LOG_VERBOSE - debug message
LOG_VERBOSE - debug message
LOG_INFORM - information message
LOG_WARN- warning
LOG_FAILURE - operation failed
LOG_MISCONFIG- misconfiguration
LOG_SECURITY - authentication or authorization failure
LOG_CATASTROPHE - nonrecoverable server error
char *func is the name of the function where the error has occurred.
Session *sn is the Session.
Request *rq is the Request.
char *fmt specifies the format for the printf function that delivers the message.