Pushed rt45293b rebased on top of current master as rt45293c.
There are two functional changes compared to rt45293b:

  - Sleep for 21 seconds instead of 20 seconds when waiting for timer
    expiration.  See the relevant comment added by commit 3d2abd0f0d for
    reasoning.

  - Place sleeps before dnssec-signzone is called instead of before
    "rndc reload ." is called (they are pointless otherwise).

Ready for review.