Slow DB / outstanding requests

[Alan DeKok]

Johan Meiring wrote:
> It was just the first time that I didn't see FR "recover" after the DB
> eventually finished with slow queries.

  I made a minor change for 2.1.12 which will clear out the pending
queue a lot more quickly.

old:
	for each new request
		clear out one "dead" request from queue

  If the dead requests originally arrived at a higher rate than the new
requests, it can take a long time to clean them out.

new:
	for each new request
		clear out all "dead" requests from queue

  Much better.

  Alan DeKok.