bugfix: avoid to re-calculate blob state for schema1
bugfix: avoid to re-calculate blob state for schema1

Use containerd.io/uncompressed label to avoid to re-calculate blob
diffID.

Signed-off-by: Wei Fu <df4176d36abdc6fd0d966de5d5471522668de494@gmail.com>

crosbymichael/containerd,containerd/containerd,miaoyq/containerd,thaJeztah/containerd,estesp/containerd,mikebrow/containerd,vdemeester/containerd,containerd/containerd,estesp/containerd,dmcgowan/containerd,thaJeztah/containerd,dmcgowan/containerd,mikebrow/containerd,miaoyq/containerd,vdemeester/containerd,crosbymichael/containerd