Dropping a key's older queue entries whenever the node ran again let a
later queued run, executing during the monitor's processing delay, take
the earlier image's entry. The snapshot taken when the image appears now
names the key's latest run, and the queue is popped by key and run:
same-key entries of earlier runs ahead of it are stale, entries of later
runs wait for their own images.
Also keeps the attribution case out of the stock real-host suite.
Vito Sansevero
b05b5dbfd9