Log Message:
powerdns: update to 4.6.4

Bug Fixes:
  - pdnsutil edit-zone, detect capitalization changes in LUA, TXT and SPF
    records

  - initialize zone cache after dropping privileges; Detect invalid bytes in
    makeBytesFromHex()

  - Log NULL for nullptr-bound properties instead of dereferencing

  - LUA records: we only need one IsUpOracle checker thread

  - axfr-retriever: abort on chunk with TC set

  - use getInnerRemote() for the remotes ring

Full changelog:
https://docs.powerdns.com/authoritative/changelog/4.6.html#change-4.6.4