Move port-mapping ownership closer to Sandbox (from Endpoint)

https://github.com/docker/libnetwork/pull/810 provides the more complete
solution for moving the Port-mapping ownership away from endpoint and
into Sandbox. But, this PR makes the best use of existing libnetwork
design and get a step closer to the gaol.

Signed-off-by: Madhu Venugopal <madhu@docker.com>
Upstream-commit: e38463b2779f455b4173171d5a1fdb115180a7e9
Component: engine

components/engine/daemon/container_operations_unix.go

@@ -775,7 +775,8 @@ func (daemon *Daemon) connectToNetwork(container *container.Container, idOrName
 
 	controller := daemon.netController
 
-	createOptions, err := container.BuildCreateEndpointOptions(n, endpointConfig)
+	sb := daemon.getNetworkSandbox(container)
+	createOptions, err := container.BuildCreateEndpointOptions(n, endpointConfig, sb)
 	if err != nil {
 		return err
 	}
@@ -801,7 +802,6 @@ func (daemon *Daemon) connectToNetwork(container *container.Container, idOrName
 		return err
 	}
 
-	sb := daemon.getNetworkSandbox(container)
 	if sb == nil {
 		options, err := daemon.buildSandboxOptions(container, n)
 		if err != nil {