Rename the Internet Explorer MIME Sniffing Security Hole Workaround Policy

Problem Definition

The name no longer really reflects what it does. What the setting actually does is change the attachment security policy. The default level is a default (secure) attachment level which uses a blacklist of content-types which are sent as attachment downloads, the "insecure" level simply sends all attachments "inline" and the "secure" attachment level sends all attachments as downloads.

Suggested Solution

Rename this something more appropriate as per how the functionality works.