Executing of reviewboard plugin with revision number instead of hash
Created originally on Bitbucket by woehrl01 (Lukas Wöhrl)
The reviewboard plugin is executed with the revision numbers instead of the hash, this leads to weird diff creations. The parent is created as the first revision - 1 which is not necessarily true.
Part which get's the revisions
The plugin should be executed with the changeset hash, and the parent should be calculated correctly