tmp: use vm-memory 0.2.1 only

Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com>

Author: liubogithub

Cargo.toml

@@ -13,7 +13,7 @@ bitflags = ">=1.1.0"
 libc = ">=0.2.68"
 log = ">=0.4.6"
 nix = ">=0.17"
-vm-memory = ">=0.2.0"
+vm-memory = "0.2.1"
 vm-virtio = { git = "https://github.com/cloud-hypervisor/vm-virtio.git", branch = "dragonball", optional = true }
 vhost-rs = { git = "https://github.com/cloud-hypervisor/vhost.git", branch = "dragonball", package = "vhost", optional = true }