Dump WU after retries when correct core cannot be found

[jcoffland]

Trac	Data
Ticket	957
Reported by	@bb30994
Status	accepted
Component	FAHClient
Priority	5

When a WU needs a new FahCore and it's not available, two things need to be retried: Downloading a new FahCore and downloading a new WU. The number of times each recovery is attempted and suitable backoff logic to avoid overloading or draining the WS must also be considered. Moreover, the QRB count of dumped WUs poses a potential problem so long pauses are required when the client cannot fix the problem.

Currently only downloading a FahCore is attempted.

Be sure appropraite data is reported to the AS.

[bb30994]

See also #1137