Set uncompressed label on diff when already exists
Set uncompressed label on diff when already exists

Diff expects to set the uncompressed label on Commit, however
if the blob already exists in the content store, no labels
will get set, requiring an Update. Check if the uncompressed
label is on the blob and set it if not.

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

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