collie/farm: save vmstate objects during cluster-wide snapshot

Without this patch, qemu's 'loadvm' command will fail after
loading cluster-wide snapshot to a new cluster.

Signed-off-by: Kai Zhang <kyle@zelin.io>
Signed-off-by: Liu Yuan <namei.unix@gmail.com>
gitignore: ignore automatically generated .8 files

Signed-off-by: Hitoshi Mitake <mitake.hitoshi@lab.ntt.co.jp>
Signed-off-by: Liu Yuan <namei.unix@gmail.com>