salt.states.archive: multiple improvments

- add a new keep paramater to optionnaly not delete the archive after extraction
- Fix the traceback in case of tar error by correctly returning a state return mapping
- Correctly handle extra tar options if any by adding defauts ones if only needed
- Pep8
- When silently extracting with tar, be sure that the no output stuff won't be
  handled as a failed extraction.
salt.states.archive: multiple improvments

- add a new keep paramater to optionnaly not delete the archive after extraction
- Fix the traceback in case of tar error by correctly returning a state return mapping
- Correctly handle extra tar options if any by adding defauts ones if only needed
- Pep8
- When silently extracting with tar, be sure that the no output stuff won't be
  handled as a failed extraction.
Merge branch 'archive' into develop