network: fix race in read access to map

Signed-off-by: Alexander Morozov <lk4d4math@gmail.com>

libnetwork/network.go

@@ -1110,8 +1110,8 @@ func (n *network) getSvcRecords(ep *endpoint) []etchosts.Record {
 	epName := ep.Name()
 
 	n.ctrlr.Lock()
+	defer n.ctrlr.Unlock()
 	sr, _ := n.ctrlr.svcRecords[n.id]
-	n.ctrlr.Unlock()
 
 	for h, ip := range sr.svcMap {
 		if strings.Split(h, ".")[0] == epName {