Add default_volume_type as cinder api parameter

Adds a parameter to set the default_volume_type for the cinder api.
Cinder-api uses this value if in CLI the parameter '--volume-type' is not
given.

Change-Id: I6cdad0a90d249bdaa2729d201cf10d3b16dd96a1
multi rbd: add opts, deprecate glance_api_version

- Add all cinder rbd params (multi-backends)
- Update documentation/tests
- Deprecate glance_api_version to avoid duplicate definition
  with cinder::glance class.
  (use glance_api_version of cinder::glance class instead.)

Change-Id: I957d81647cd0320a52be00dceff23692ba208017
Merge "Add default_volume_type as cinder api parameter"
Add log_dir param. by default and allow users to disable it

This commit add log_dir param and configures it to /var/log/cinder
(default location). Set log_dir to false allows users to disable logging
to a directory (usefull if syslog is enabled in order not to log twice).

Change-Id: I8b8d72f8c9551ffb1a4f73575013d70e985f274c
Closes-bug: #1282296
[vmdk] Replaced pip with native package manager

Change-Id: I0603889ad00cbd7fe83c436f1c7273ef0c35b73f
Merge "Add log_dir param. by default and allow users to disable it"