fix typo and naming convention

   o Availability:

     - Must be available to upgrade within a few days in most cases.

       (While we're still developing Tor, we periodically find bugs that

       impact the whole network and require dirserver upgrades.)

     - Should be have a well-known way to contact the administrator

       impact the whole network and require authority upgrades.)

     - Should have a well-known way to contact the administrator

       via PGP-encrypted message.

   o Integrity:

   o Diversity

     - We should avoid situations that make it likelier for multiple

       dirserver failures to happen at the same time.  Therefore...

       - It's good when dirservers are not all in the same country.

       - It's good when dirservers are not all in the same jurisdictions.

       - It's good when dirservers are not all running the same OS.

       - It's good when dirservers are not all using the same ISP.

       - It's good when dirservers are not all running the same

       authority failures to happen at the same time.  Therefore...

       - It's good when authorities are not all in the same country.

       - It's good when authorities are not all in the same jurisdictions.

       - It's good when authorities are not all running the same OS.

       - It's good when authorities are not all using the same ISP.

       - It's good when authorities are not all running the same

         version of Tor.

       - No two dirservers should have the same operator.

       - No two authorities should have the same operator.

     - Maximal diversity, however, is not always practical.  Sometimes,

       for example, there is only one version of Tor that provides a

       given consensus generation algorithm.