Version control features are added by Tableau to Tableau Server since the time that this answer was originally provided.
Currently, Tableau Server does not provide version control functionality. There are a few ideas on the Tableau Community forum requesting integration with version control software such as Git or for version control to be baked into Tableau Server. As Tableau workbooks are just XML files, then one could use some form of source control software for workbooks stored on a shared drive, and for publishing permissions to be restricted to a site/project admin
In theory, a script could tie all of these components together. If a particular version of a Tableau workbook were associated with a specific database and ETL change (although I'm not sure what part the Python script plays here), then the previous version of the workbook could be retrieved from source control and republished as part of a rollback