Vendoring in libnetwork with the fix for compilation error using GCCGo (X86 GCCGO CI)

Signed-off-by: Srini Brahmaroutu <srbrahma@us.ibm.com>

hack/vendor.sh

@@ -20,7 +20,7 @@ clone git github.com/tchap/go-patricia v2.1.0
 clone git golang.org/x/net 3cffabab72adf04f8e3b01c5baf775361837b5fe https://github.com/golang/net.git
 
 #get libnetwork packages
-clone git github.com/docker/libnetwork f5423a097e5da89f9ea206ddf8b93b5ac1f51ee7
+clone git github.com/docker/libnetwork 70409acbcd661e6a7bfe04e2b81412a465d29512
 clone git github.com/armon/go-metrics eb0af217e5e9747e41dd5303755356b62d28e3ec
 clone git github.com/hashicorp/go-msgpack 71c2886f5a673a35f909803f38ece5810165097b
 clone git github.com/hashicorp/memberlist 9a1e242e454d2443df330bdd51a436d5a9058fc4

vendor/src/github.com/docker/libnetwork/drivers/overlay/overlay.go

@@ -101,7 +101,6 @@ func Fini(drv driverapi.Driver) {
 }
 
 func (d *driver) configure() error {
-	var onceDone bool
 	var err error
 
 	if len(d.config) == 0 {
@@ -109,8 +108,6 @@ func (d *driver) configure() error {
 	}
 
 	d.Do(func() {
-		onceDone = true
-
 		if ifaceName, ok := d.config[netlabel.OverlayBindInterface]; ok {
 			d.ifaceName = ifaceName.(string)
 		}