Better error handling when you click on the Export Everything button when you do not have any saved objects.

[rashmivkulkarni]

Steps to reproduce:

• Install 5.0-alpha1 RC2 and X-Pack in ES and Kibana per ticket elastic/dev#653
• Configure Kibana to talk to ES
• Login as the user which you have configured as per security docs. ( kibana_user)
• Navigate to Visualizations and click on the Objects tab .
• If you DONOT have any saved objects( such as saved searches) to edit and if you click on the
  Export Everything button, you see the following error which can be handled more gracefully conveying the actual message.

Uncaught TypeError: Cannot read property 'hits' of undefined (http://0.0.0.0:5601/bundles/kibana.bundle.js?v=11105:60)
Version: 5.0.0-snapshot
Build: 11105
Error: Uncaught TypeError: Cannot read property 'hits' of undefined (http://0.0.0.0:5601/bundles/kibana.bundle.js?v=11105:60)
    at window.onerror (http://0.0.0.0:5601/bundles/commons.bundle.js?v=11105:86:18668)

[spalger]

Thanks @Rasroh, fixed this in #6774