Rename atomicWrite to writeToCompletion
Rename atomicWrite to writeToCompletion

Signed-off-by: Shiming Zhang <8c543c05fed97d4f3769204e242efc8a41a67560@foxmail.com>

dmcgowan/containerd,containerd/containerd,mikebrow/containerd,containerd/containerd,mikebrow/containerd,thaJeztah/containerd,dmcgowan/containerd,estesp/containerd,thaJeztah/containerd,estesp/containerd