One of the last big gaps with novaclient. As noted in the release note,
the current '--block-device-mapping' format is based on the old BDM v1
format, even though it actually results in BDM v2-style requests to the
server. It's time to replace that.
Change-Id: If4eba38ccfb208ee186b90a0eec95e5fe6cf8415
Signed-off-by: Stephen Finucane <sfinucan@redhat.com>