Bug #1079 - Don't use users real host and IPs when matching against

bans and excepts, except when a user is unbanning themselves, in an
attempt to prevent people from gaining other users IPs.
This removes support for Unreal and Bahamuts SVSMode -b because
it will unban users by real host and IP.

src/dns.cpp

@@ -559,7 +559,6 @@ void DNSManager::Tick(time_t now)
 
 	for (std::multimap<Anope::string, DNSRecord *>::iterator it = this->cache.begin(), it_next; it != this->cache.end(); it = it_next)
 	{
-		Anope::string host = it->first;
 		DNSRecord *req = it->second;
 		it_next = it;
 		++it_next;