dnssec: avoided using keytag as a false-unique key identifier

Closes #496

See merge request !634

Libor Peltan authored 8 years ago and Daniel Salzman committed 8 years ago

instead, if obtaining key by keytag is necessary, we walk through all the matching keys and choose the appropriate one

Notify ignore same serial

See merge request !635

Events refactoring

See merge request !587

* origin/master: (193 commits)

- We have to cancel the timer before scheduling for a fixed time.
- We cannot cancel the timer if the zone is expired based on time,
  because the expire handler may not have been called yet.

The requestor can interrupt normal execution flow in case of
encountering for instance a malformed packet. The cleanup has to be
executed even in that case.

dnssec: online signing can use both current and legacy keystore config

Closes #494

See merge request !620