Logs progress catching up to master in HA

Possible after a refactoring where the response unpacker now accepts a
TxHandler in its accept method. This makes it possible to reuse a single
response unpacker for multiple TxHandler purposes, and by extension a
single MasterClient instance for multiple purposes.
Merge pull request #3185 from tinwelint/2.2-response-unpacker-handler

[2.2] Logs progress catching up to master in HA