Updated behaviors and configs for volumes v1

* Added defaults for properties in volumes_api/config.py
* Moved snapshot create logic in volumes_api/behaviors.py to it's own
  method.
* Updated behavior methods to use config defaults instead of hard-coded
  defaults.
* Fixed a bug in volume status progression method

Change-Id: Ia6504ee2344f428b3e47fb1c65e504a3b3883e80
Merge "Updated behaviors and configs for volumes v1"