reuse kvm_vm_ioctl

reuse kvm_vm_ioctl

Start using kvm_vm_ioctl's code.
For type safety, delete vm_fd from kvm_context entirely, so the
compiler can play along with us helping to detect errors I might
have made.

Also, we were slightly different from qemu upstream in handling error
code from ioctl, since we were always testing for -1, while kvm_vm_ioctl
returns -errno. We already did this in most of the call sites, so
this patch has the big advantage of simplifying call sites.

Diffstat says:
 4 files changed, 58 insertions(+), 134 deletions(-)

Signed-off-by: Glauber Costa <glommer@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>