Fix hostname construction for DNSBL checking
DNSBL needs the octects in the ip address to be reversed before
appending the database zone when constructing the hostname to be
checked, see http://en.wikipedia.org/wiki/DNSBL#DNSBL_queries
Without the attached patch wgEnableSorbs is totally useless
(this is certainly true if you use spamhaus as DNSBL service).
Please consider applying this patch as soon as possible.