Fix ctr delete to remove snapshot
Fix ctr delete to remove snapshot

Fix the behavior of removing snapshot on container delete.
Adds a flag to keep the snapshot if desired.

Signed-off-by: Derek McGowan <e1c79a582b6629e6b39e9679f4bb964d25db4aa8@mcgstyle.net>

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