Add attach/detach blockstorage support

[j-griffith]

Add volumeactions extension to blockstorage module. For now just start with basic attach and detach commands and their associated helpers.

Note that extensions are currently API version independent in Cinder and are shared regardless of configured Cinder API endpoint.

Add the following Cinder calls:

• reserve
• initialize_connection
• attach
• unreserve
• terminate_connection
• detach

For information on Cinder attach/detach workflow see: http://docs.openstack.org/developer/cinder/devref/attach_detach_conventions.html

[coveralls]

Coverage decreased (-0.07%) to 80.106% when pulling 1c3f911626cfd8ca26d14ed5ab454e9949a3b62c on j-griffith:attach_detach_volumes into c54bbac81d19eb4df3ad167764dbb6ff2e7194de on rackspace:master.

[j-griffith]

I missed the earlier work around V2 here: https://github.com/rackspace/gophercloud/pull/489/commits/7516fde1624dab55990845c6f34f14b98f7dca56

I'll have a look at what I may have missed that's in there, or if that PR has a chance of being re-opened and reviewed I'm happy to help out. I just need to get attach/detach somewhat soonish.

[jamiehannaford]

@j-griffith I'm going to review 7516fde ASAP. At first glance, it seems that it provides what you need to get your Docker plugin to work. The only caveat is that it's been nested under a v2 directory, which I'll ask the submitter to address. Do you know any docs that makes this version independent stuff explicit? I couldn't find any.

[j-griffith]

Thanks Jamie, I'll load that up and give it a go. Note I commented on that PR WRT the versions. TLDR, no we don't really explicitly document that in Cinder, but the organization of the modules is fairly clear. Also this will all change during the next six months on the cinder side and we will probably have to update/revisit here and impl micro versions.