Readme fix

On creating a new Okta object the readme just states to enter 'your domain,' so I passed 'company.okta.com' (the full subdomain).  Doing this causes the request in NetworkAbstraction to generate a hostname of 'company.okta.com.okta.com' which causes Node to throw a very obscure SSL error on every request.  Specifying that okta.com should not be included should help other people avoid the same dumb mistake.