Fix missing import for "scope" package

I believe this happened due to conflicting PR's that got merged without
CI re-running between them.

Signed-off-by: Brian Goff <cpuguy83@gmail.com>

libnetwork/sandbox_store.go

@@ -9,6 +9,7 @@ import (
 	"github.com/containerd/log"
 	"github.com/docker/docker/libnetwork/datastore"
 	"github.com/docker/docker/libnetwork/osl"
+	"github.com/docker/docker/libnetwork/scope"
 )
 
 const (

libnetwork/store.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/containerd/log"
 	"github.com/docker/docker/libnetwork/datastore"
+	"github.com/docker/docker/libnetwork/scope"
 )
 
 func (c *Controller) initStores() error {