Requests for an occurrence record not found shows "Application Error"

[nickdos]

E.g. https://biocache.ala.org.au/occurrences/7563b168-57cb-4970-9b3a-a4585e4b8db6

Example is an occurrence record ID from databox, so it should just be treated as a "Not found" 404 page.
It's only if you read the "error details" and happen to know that buried code 404 (see below) is the "page not found" code, that you could tell this was a case of the ID not being found.

Current behaviour

Application error
Failed to get json from web service (https://biocache-ws.ala.org.au/ws/occurrences/7563b168-57cb-4970-9b3a-a4585e4b8db6) status 404 : Failed calling web service - service returned HTTP 404

Expected behaviour

Page not found
The requested record was not found. The supplied record ID is either incorrect or has been removed or replaced.

[adam-collins]

Added an overridable view occurrenceNotFound.gsp.