Fix indenting for comments in ConfigValidator

The Rubydoc comments under the heading 'Recursion in this class' were
being formatted as code by [Yard](http://yardoc.org/) because of they
were indented.

Fix the indentation so that the comments are formatted correctly.
Rubydoc comments were showing for module not class

Move the Rubydoc comments intended for the Vcloud::Core::ConfigValidator
class.

[Yard](http://yardoc.org/) was associating these comments to the
`Vcloud` module; move them so that they appear under the
`ConfigValidator` class.
Merge pull request #73 from alphagov/fix-rubydoc

Fix Rubydoc comments for Vcloud::Core::ConfigValidator