Update storage kind test
Update storage kind test

Testing proto and snapshot kinds are equivalent when cast to each other.

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

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