windows: mitigate possible escalation of privileges
windows: mitigate possible escalation of privileges

Reported by @zubrahzz

ref. https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-28169

In the previous version, NT AUTHORITY\Authenticated Users:(I)(M) is
granted. It means that logged in users can replace any files under
opt/td-agent/bin. It also allows for attacker to gain administrative
privileges by replacing these files because these files are executed
as a local services with SYSTEM privilege.

Note that this PR was merged, we need to update gems
by td-agent-gem with administraror privilege.

Signed-off-by: Kentaro Hayashi <f80b60a638b9855e938d3bbb8dcd3c74d400b0aa@clear-code.com>

treasure-data/omnibus-td-agent,treasure-data/omnibus-td-agent,treasure-data/omnibus-td-agent