Revert "Use dLen in TSIG too"
Revert "Use dLen in TSIG too"

This reverts commit 37406413d78beaee391e3b15ae5a45e6173c3a43.

skynet/dns,skyportsystems/dns,benbearchen/dns,flebarbe/dns,letsencrypt/dns,Git-Host/dns,janstk/dns,Psiphon-Inc/dns,FiloSottile/dns,jdef/dns,josephyzhou/dns,rolandshoemaker/dns,tsenart/dns,AlexCheong/dns,modulexcite/dns,curtiszimmerman/dns,bboreham/dns,jmhodges/dns,ym/go-dns,miekg/dns,bragr/dns,ezoic/dns,hugozhu/dns,ErikDubbelboer/dns,asergeyev/dns,cloudflare/dns,michaelharo/dns,tempbottle/dns