Log an unexpected error that was encountered.

The stack trace did not make it evidant which request had caused this
issue, so add extra logging for the request that caused it.  Sanitize
this request if it may contain any secrets.

Additionally, in this situation, begin shutting down the wallet rather
than simply dropping the response.  This will help to catch the issue
since it's easier to notice all requests failing, rather than just one
that was dropped.  If shutdown takes an unreasonably long time, panic.