Fix security issue in _prolog_error().

Fix security issue caused by insecure file path handling triggered by
the failure of a Prolog script. To exploit this a user needs to
anticipate or cause the Prolog to fail for their job.

(This commit is slightly different from the fix to the 15.08 branch.)

CVE-2016-10030.
static int _waiter_complete (uint32_t jobid)
{
	return (list_delete_all (waiters, (ListFindF) _find_waiter, &jobid));
}

static int _waiter_complete (uint32_t jobid)
{
	return (list_delete_all (waiters, (ListFindF) _find_waiter, &jobid));
}
