Remove auth-staging.g5devops.com references

We're not using auth-staging for anything except testing auth. The docs still mentioned it as a place to set up your local development auth apps. That's fine, except they often wipe the staging DB for testing. Anybody working on auth changes that break things will also break everybody's local development. So, for the foreseeable future, prod.

README.md

@@ -75,9 +75,7 @@ root to: 'home#index'
 
 ### Registering your OAuth application
 
-1. Visit the auth server admin console and login:
-  * For development, visit https://auth-staging.g5devops.com/admin
-  * For production, visit https://auth.g5search.com/admin
+1. Visit the auth server admin console and login to https://auth.g5search.com/admin
 2. Click "New Application"
 3. Enter a name that recognizably identifies your application.
 4. Enter the redirect URI where the auth server should redirect
@@ -90,8 +88,7 @@ root to: 'home#index'
    http://localhost:3000/g5_auth/users/auth/g5/callback is fine if your browser
    and client application server are both local).
 
-   If you are using the production G5 Auth server, the redirect URI **MUST**
-   use HTTPS.
+   If you have a production application, the redirect URI **MUST** use HTTPS.
 5. For a trusted G5 application, check the "Auto-authorize?" checkbox. This
    skips the OAuth authorization step where the user is prompted to explicitly
    authorize the client application to access the user's data.
@@ -106,8 +103,7 @@ environment variables for your client application:
 * `G5_AUTH_CLIENT_SECRET` - the OAuth 2.0 application secret from the auth server
 * `G5_AUTH_REDIRECT_URI` - the OAuth 2.0 redirect URI registered with the auth server
 * `G5_AUTH_ENDPOINT` - the endpoint URL (without any path info) for the G5 auth server.
-  Generally, this will be set to either `https://auth-staging.g5devops.com` or
-  `https://auth.g5search.com` (the default).
+  Generally, this should be `https://auth.g5search.com`.
 
 If you need to make server-to-server API calls that are not associated with an
 end user, you can also set up a default user's credentials with: