Revert "Swallow a NotFound error when deleting content, to support schema 1 manifests"

This reverts commit 92101de156 from #296.

This was the wrong approach a subsequent commit will fix this properly.

Signed-off-by: Ian Campbell <ijc@docker.com>

source/containerimage/pull.go

@@ -258,7 +258,7 @@ func (p *puller) Snapshot(ctx context.Context) (cache.ImmutableRef, error) {
 	}
 
 	for _, nl := range notLayerBlobs {
-		if err := p.is.ContentStore.Delete(ctx, nl.Digest); err != nil && !errdefs.IsNotFound(err) {
+		if err := p.is.ContentStore.Delete(ctx, nl.Digest); err != nil {
 			return nil, err
 		}
 	}