remove temporary dir
remove temporary dir

The temporary directory had better to be removed after test case
finished.

Signed-off-by: xiekeyang <43239a1d761bfde9c48de11b7981f737d518cda0@huawei.com>

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