Only log "IDENT ... no result" when IDENT was looked up

Without this patch, ngIRCd logged the "IDENT lookup for connection X:
no result"-message even when IDENT lookups have been disabled using the
"Ident = no" configuration option, which is a little bit misleading.

Reported by "btwe" in #ngircd.
Don't enforce channel types for other servers

The configuration option "AllowedChannelTypes" must only be enforced for
regular clients and not for remote servers. Channels created by other
servres are always allowed, because they already exist and the daemon
must stay in sync with the network.
getpid.sh: use /bin/pidof when available
Commands.txt: Document proprietary DIE <message> parameter