Merge in some commits from upstream..

Merge in some commits from upstream..

- Fix that failure to add tcp to tcp base does not leak the socket.
- Fixes for wildcard addition and deletion, speedup for some cases.
- Fix that queries for noname CH TXT are REFUSED instead of nodata.
- Fix #616: retry xfer for zones with no content after command.
- Fix that expired zones stay expired after a server restart.
- RFC 7344: CDS and CDNSKEY (read in).

ok sthen@