This removes the majority of the nova-volume code from the codebase.
It updates relevent config options to default to cinder. It updates a
number of existing tests that were depending on code that was removed.
A few things still need to be removed:
* volume/driver.py & volume/iscsi.py
These files are used by the libvirt volume driver tests. These
tests should be updated to mock the relevant calls.
* scheduler/simple.py & scheduler/multi.py
These files should no longer be necessary so they can be removed
in a subsequent patch
* exception.py cleanup
Once the above files are removed there are a number of unused
exceptions which can be removed
* database calls and database tables
The database calls have not been removed and the tables have not
been dropped. This can be done in a separate migration
* additional config options and nova.conf.sample
There may be a few extra config options that can be removed and the
conf sample can be regenerated
Implements bp delete-nova-volume
Change-Id: I0b540e54dbabd26901a7530035a38583bb521fda
7e2b93acc5