Nautilus UI change

[Dave Camp <dave ximian com>]

For security reasons, nautilus has to pop up a dialog and refuse to
activate if the sniffed mime type doesn't match the extension.  This
will involve a dialog explaining the problem and how to fix it.

It will be an annoying change to document and a slightly annoying one to
translate, but we need it for security reasons.

Any objection to me putting this in and sending a patch to the relevant
lists when it's ready?

-dave