Auth failure from docker entry point script is confusing

[a1exsh]

Let's try to set the admin password in a different way that doesn't spam the logs on every start with these:

Connection error: ('Unable to connect to any servers', {'127.0.0.1': AuthenticationFailed(u'Failed to authenticate to 127.0.0.1: code=0100 [Bad credentials] message="Username and/or password are incorrect"',)})  

[a1exsh]

Maybe we could do this only if some special env var is set. The create cluster script will set it for the 1st node it starts, but not the others. Update cluster script will remove this env var from user data whenever it sees one.