nsupdate: soa lookup should be using tcp when "-v" is given
Description
nsupdate offers the switch -v to use tcp for update requests. But before sending that update request nsupdate gathers the SOA using a udp connection, and there's currently no way I know of to change that.
As nsupdate is already able to use a different port both for querying the SOA and for sending update requests, it'd be a nice feature to have nsupdate honor the -v option for the SOA query as well.
Use case: I'm running a dns-over-tls setup using bind together with stunnel. The tunnel's endpoint must be tcp and nsupdate is not able to get the SOA over that tunnel.
Request
Please make nsupdate honor -v for SOA queries as well.