Log Message:
net/dnsdist: Update to 1.5.1

* Released: 1st of October 2020
* Improvements:
  - Add the "clearConsoleHistory" command

* Bug Fixes:
  - Stop the related responder thread when a backend is removed
  - Fix getEDNSOptions() for {AN,NS}COUNT != 0 and ARCOUNT = 0
  - Fix building with LLVM11 (@RvdE)
  - Only add EDNS on negative answers if the query had EDNS