Dynamic reconfig of discovery endpoint not updating endpoints in all cases

[c00crane]

If Social client is reconfigured in the following steps, it will not set the authorization, token, ... endpoints.

1. configure server with a valid discoveryEndpointUrl attribute and none of the discoverable config attributes set
2. start the server
3. Update the server config - replace the discoveryEndpointUrl value with ""
4. Note the message in the server's messages.log: CWWKS5500E: A required configuration parameter authorizationEndpoint is missing or has an invalid value null
5. Update the server config again - replace the discoveryEndpointUrl value with the original good discovery endpoint.
6. Note the message in the server's messages.log: CWWKS5500E: A required configuration parameter authorizationEndpoint is missing or has an invalid value null
7. Attempt to access a social login protected app, you'll receive a 403 in the response and find this message in the server log: CWWKS5500E: A required configuration parameter authorizationEndpoint is missing or has an invalid value null

It looks like the initial config sets up the discoveryDocumentHash which is used to populate the config.
The second config finds that the discovery endpoint is not set, so, it skips using the discoveryDocumentHash and tries to init the config from the values found in server.xml.
The hash instance is still set to the values from the first config.
The third config comes along and runs discovery. If then compares the current discoveryDocumentHash to the still existing discoveryDocumentHash - they're the same, so, it skips setting the values into the config object.

We need to do one of two things:

1. when we find that the discovery endpoint is not set, we should discard the discoveryDocumentHash (I'm not sure if we can get to the hash at that point to do this)
2. stop checking if the discoveryDocumentHash values are the same and if set, always set the config values from the hash. (I don't know why that check was put in place - could we be breaking something else if we make this change)