content: provide more context for lockfile error
content: provide more context for lockfile error

Signed-off-by: Stephen J Day <63efd86fa22882ae89b6027b22a36e4db1f4214d@docker.com>

miaoyq/containerd,xiekeyang/containerd,mikebrow/containerd,containerd/containerd,estesp/containerd,rajasec/containerd,Wolphin-project/containerd,hqhq/containerd,dmcgowan/containerd,thaJeztah/containerd,vdemeester/containerd,vdemeester/containerd,crosbymichael/containerd,AkihiroSuda/containerd,mikebrow/containerd,chanezon/containerd,dmcgowan/containerd,miaoyq/containerd,thaJeztah/containerd,containerd/containerd,kunalkushwaha/containerd,yuexiao-wang/containerd,estesp/containerd,kunalkushwaha/containerd,lichao-mobanche/containerd,docker/containerd,crosbymichael/containerd