fix shim std logs not close after shim exit
fix shim std logs not close after shim exit

Signed-off-by: Jing Rui <427364c6355b027d3fb0d131a4d5a3451662391d@huawei.com>

mikebrow/containerd,mikebrow/containerd,estesp/containerd,crosbymichael/containerd,thaJeztah/containerd,dmcgowan/containerd,containerd/containerd,estesp/containerd,containerd/containerd,crosbymichael/containerd,dmcgowan/containerd,vdemeester/containerd,thaJeztah/containerd,vdemeester/containerd