cpe_logger: README describes fluent-bit egress, not osquery

Summary: The README claimed cpe_logger.log can be collected by osquery. No osquery table, ATC entry, or pack reads that file; cpe_base_settings::fluentbit_files tails it and scribbles it to the Scribe category cpe_logger. The only osquery relationship runs the other way – cpe_gk‘s osquery_arch_audit.sh appends osquery findings into the log.

Also corrects the path in the opening line, which read /var/log/cpe/cpe_logger.log; CPE::Log.log_path is /var/log/cpe_logger.log.

Differential Revision: D122010157

fbshipit-source-id: 533854ea15822804de0ecaa346d0530f100bac4b