Update config.map schema.

- Specify release queue as well in the `config.map` file.
- Keep track of all the release queues, so that we just checkout the default
  branch and then move to the appropriate one specified in config.map.
Merge pull request #317 from ktf/add-all-releases

Update config.map schema.
Merge remote branch 'origin/IB/CMSSW_7_0_X/stable' into IB/CMSSW_7_0_X/stable