Made failure to find tempjobs cleanup file ok

Can show up in test logs if users run more than
one TJ test concurrently, and since this isn't
a real error, it's just suppressed for now.
What would you think about making this a debug message? That would make it match this log message from earlier in the function, which can also be caused by a file getting deleted by a test running in parallel.

    log.debug("Unable to create JobPrefixFile for {}", file.getPath());