Pull in the FlavorExtraData extension, add vcpus to flavor.detail output
(LP: 849160, LP: #829687)
This cherry picks trunk commit 1574, which merged a branch to the
FlavorExtraData extension. The extension provides additional data
flavors.detail.
Bug 849160: provides 'rxtx_cap', 'rxtx_quota', 'swap' fields
Bug 829687: provides the 'vcpus' data that should have been there
per the openstack 1.1 api spec.
For 'python-novaclient' package, this means that 'nova flavor-list' will have
data for all its output fields.