This patch adds the policy for creating and retyping volumes
with volume types that indicate multi attach capabilities.
There are two policies being added:
1. MULTIATTACH_POLICY
General policy to disallow creating volumes of type multiattach
as well as retyping volumes to/from a multiattach type.
2. MULTIATTACH_BOOTABLE_VOLUME_POLICY
Specific policy to disallow creating multiple attachments for
any volume that is `bootable`.
We use policy to control the use of this particular type,
and we also limit the ability to retype a volumes
multi attach settings to only volumes that are in available
status. We need to to do this because multi attach has
implications for things on the Compute side (ie libvirt)
that would require detach/reattach to keep things synced
correctly.
Currently there's no back end reporting the `multiattach=True`
capability, that will be in the next patch of this series.
Change-Id: I3fd8afe9cbae3c733a6530dce7be6fef8d53cfa6
blueprint: multi-attach-v3-attach
f38e77cb18