ctr shim exec: fix cli flag
ctr shim exec: fix cli flag

Signed-off-by: Akihiro Suda <ea940da7e429af3d0d0c18296cabd0112a36bad5@lab.ntt.co.jp>

chanezon/containerd,estesp/containerd,dmcgowan/containerd,AkihiroSuda/containerd,hqhq/containerd,rajasec/containerd,dmcgowan/containerd,miaoyq/containerd,kunalkushwaha/containerd,mikebrow/containerd,xiekeyang/containerd,thaJeztah/containerd,miaoyq/containerd,mikebrow/containerd,vdemeester/containerd,estesp/containerd,crosbymichael/containerd,crosbymichael/containerd,containerd/containerd,kunalkushwaha/containerd,thaJeztah/containerd,containerd/containerd,vdemeester/containerd