chkuser 2.0.8 logging format

When #defines for logging are enabled, chkuser patch emits log informations
on the same qmail-smtpd log destination

This is the log format:

    CHKUSER "brief message": \
	    from <sender:remoteinfo:relayclient> \
	    remote <helo:remotehostname:remotehostip> \
	    rcpt <recipient> : "extended message"

where
	brief message 	
		    * accepted rcpt
		    * relaying rcpt
		    * rejected relaying
		    * rejected rcpt
		    * no auth resource
		    * mbx overquota
		    * rejected intrusion
		    * intrusion threshold
		    * rejected sender

	sender 	sender declared within "mail from"

	remoteinfo	the value of "TCPREMOTEINFO" or the autenticated user

	relayclient 	the value of RELAYCLIENT env variable (be careful to set it,
			inside your tcp.cdb with a value that let you understand who is sending)

	helo 		helo declared from remote system

	hostname 	the value of "TCPREMOTEHOST"

	remotehostip 	the value of "TCPREMOTEIP"

	recipient 	recipient address

	extended message 	this field has more wide description for
				some generic "brief message":
			accepted rcpt 	found existing recipient
			relaying rcpt 	client allowed to relay
			rejected relaying 	client not allowed to relay
			rejected rcpt 	not existing recipient
			rejected rcpt 	max number of recipients
			rejected rcpt 	max number of invalid recipients
			rejected rcpt 	invalid rcpt address format
			rejected rcpt 	invalid rcpt MX domain
			intrusion threshold 	max number of allowed rcpt
			intrusion threshold 	max number of allowed invalid rcpt
			rejected intrusion 	rcpt ignored, session over intrusion threshold
			no auth resource 	no auth resource available
			mbx overquota 	rcpt mailbox is overquota
			rejected sender 	invalid sender address format
			rejected sender 	invalid sender MX domain