[development] Requiring node revisions

[Robert Douglass]

This speaks to a need for "access own node-type revisions" vs "access 
node-type revisions" permission, imo.

Karthik wrote:
>
> One of many scenarios where this will prove to be a hindrance:
>
> 1. I create a page using the PHP filter containing sensitive information.
> 2. I forget to select the PHP input format.
> 3. I notice this and edit the page again and select the correct format.
> 4. I think all is well.
>
> Anybody who can view revisions will be able to see my sensitive 
> information.
>
> -K
>