Removing the unused Index enum.

-- Also modified the InitStateHolder to take an iterator which works well with filtering by interest.
-- Provided a shutdown() on registry so that we can simulate end of an index.
Increasing the maximum wait time for the test.

Cloudbees servers are sometimes slow which can result in flakiness of the test.
Merge pull request #166 from NiteshKant/2.x

Removing the unused Index enum.