Finished release v0.2.12.

* release/v0.2.12:
  STORAGEMODEL-307 ensuring methods that iterate over device don't fail in case one device is not working as expected
  buildout.cfg: changed isolated python version to v2.7.6.21
  buildout.cfg: changed isolated python version to v2.7.6.20
  buildout.cfg: changed isolated python version to v2.7.6.19