Improve logging in StatusCheck timer

[brianritchie1312]

StatusCheck.poll() currently catches and logs any Exceptions; but logs only the original message. It would be more useful if it added a more specific indication to the message.
Similarly, determining the cause of an expunged timer thread in glassfish can be difficult. I propose adding a catch-log-and-rethrow for all other Throwables. This is not considered good practice generally, but may improve traceability.
See also: icatproject/icat.utils#8 (comment)

[brianritchie1312]

I stand corrected on the first part of this: errors logged to topcat.log do indicate that they are from StatusCheck; so there is no need to add extra text to the log message.
I have some evidence that suggests they still count as failures that may trigger glassfish to expunge the timer.

[brianritchie1312]

8d7984c added logging to StatusCheck to record prepareData and isPrepared requests on the IdsClient and any resulting changes to Download status.