status command fails when the ASG contains terminated instances in it

[kaushik]

When we terminate an instance and bring it out of service, then the status command fails for that stack because it tries get info from the terminated instance.

/.rvm/gems/ruby-2.2.3@api/gems/moonshot-0.7.0/lib/moonshot/stack_asg_printer.rb:117:in `instance_row': undefined method `public_ip_address' for nil:NilClass (NoMethodError)
  from /.rvm/gems/ruby-2.2.3@api/gems/moonshot-0.7.0/lib/moonshot/stack_asg_printer.rb:103:in `block in create_instance_table'
  from /.rvm/gems/ruby-2.2.3@api/gems/moonshot-0.7.0/lib/moonshot/stack_asg_printer.rb:102:in `map'
  from /.rvm/gems/ruby-2.2.3@api/gems/moonshot-0.7.0/lib/moonshot/stack_asg_printer.rb:102:in `create_instance_table'
  from /.rvm/gems/ruby-2.2.3@api/gems/moonshot-0.7.0/lib/moonshot/stack_asg_printer.rb:29:in `block in print'
  from /.rvm/gems/ruby-2.2.3@api/gems/moonshot-0.7.0/lib/moonshot/stack_asg_printer.rb:17:in `each'
  from /.rvm/gems/ruby-2.2.3@api/gems/moonshot-0.7.0/lib/moonshot/stack_asg_printer.rb:17:in `print'
  from /.rvm/gems/ruby-2.2.3@api/gems/moonshot-0.7.0/lib/moonshot/stack.rb:87:in `status'
  from /.rvm/gems/ruby-2.2.3@api/gems/moonshot-0.7.0/lib/moonshot/controller.rb:35:in `status'
  from /.rvm/gems/ruby-2.2.3@api/gems/moonshot-0.7.0/lib/moonshot/cli.rb:116:in `status'
  from /.rvm/gems/ruby-2.2.3@api/gems/thor-0.19.1/lib/thor/command.rb:27:in `run'
  from /.rvm/gems/ruby-2.2.3@api/gems/thor-0.19.1/lib/thor/invocation.rb:126:in `invoke_command'
  from /.rvm/gems/ruby-2.2.3@api/gems/thor-0.19.1/lib/thor.rb:359:in `dispatch'
  from /.rvm/gems/ruby-2.2.3@api/gems/thor-0.19.1/lib/thor/base.rb:440:in `start'
  from ./bin/environment:94:in `<main>'