Description of problem:

Not sure which component to choose.

When clicking Add a new Cloud Volume from the Configuration Menu, the page shows a management engine error with the text:

undefined method `sub_table' for nil:NilClass [cloud_volume/button]

Version-Release number of selected component (if applicable):
5.6.0.12

How reproducible:
Was working in 5.6.0.10, but not in 5.6.0.12

Steps to Reproduce:
1.  Navigate to Compute:Cloud:Volumes
2.  From Configuration menu, choose Add new Cloud Volume
3.

Actual results:
Generic Page error - Unexpected error encountered

Expected results:
In 5.6.0.10, it loaded the page correctly.

Additional info:
This menu item should be disabled unless an appropriate cloud provider exits.  The feature has no meaning in Azure.