Fix error reporting (#128)

Put error back in the correct place in the directives.go. Also don't
make it a pointer. If it *is* a pointer the buildstack function does
not correctly set the Next Handler. Don't understand *why* this is
different from Caddy. Anyway this fixes it, with the caveat that
the error log file is now openend earlier in the startup.

Fixes #127

middleware/etcd/handler.go

@@ -73,7 +73,6 @@ func (e Etcd) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (i
 		return e.Err(zone, dns.RcodeNameError, state)
 	}
 	if err != nil {
-		println("returning error", err.Error())
 		return dns.RcodeServerFailure, err
 	}