Change the passphrase of the encrypted history, re-encrypting it with the new one.
The daemon prompts for the passphrases itself: they never travel over the bus.
| this |
a Client instance |
| cancellable |
a Cancellable to abandon the call with |
| callback |
a TaskReadyCallback to call once the request is satisfied, or null to ignore the result |
| user_data |
the data to pass to |