restapi : missing cpu mode option in both add and update vm(#916700)

When adding / updating Vm using the CLI, the cpu-mode option is
missing in the available options

Change-Id: I1d08f77ceecc45253a0b9997c4c43e0bd995ac9a
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=916700
Signed-off-by: Ravi Nori <rnori@redhat.com>