MB-9307: Add test for indexable/undindexable switch

Add a test for the rollback when a partition changes from
unindexable to indexable.

Change-Id: I99414a2d81c8c90da3281e59aa925e1e55856c52
Reviewed-on: http://review.couchbase.org/30860
Reviewed-by: Filipe David Borba Manana <fdmanana@gmail.com>
Tested-by: Volker Mische <volker.mische@gmail.com>