[Falcon] SONA : Supports port-create without fixed IPs

Change-Id: I3a37540480912849f03e8880cc8c9b387c6bc613

@@ -161,7 +161,9 @@ public class OpenstackSwitchingManager implements OpenstackSwitchingService {
 
     @Override
     public void createPorts(OpenstackPort openstackPort) {
-        registerDhcpInfo(openstackPort);
+        if (!openstackPort.fixedIps().isEmpty()) {
+            registerDhcpInfo(openstackPort);
+        }
     }
 
     @Override

@@ -73,7 +73,7 @@ public class OpenstackPortCodec extends JsonCodec<OpenstackPort> {
         for (JsonNode fixedIpInfo: fixedIpList) {
             String subnetId = fixedIpInfo.path(SUBNET_ID).asText();
             String ipAddressStr = fixedIpInfo.path(IP_ADDRESS).asText();
-            if (ipAddressStr != null) {
+            if (!fixedIpInfo.path(IP_ADDRESS).isMissingNode() && ipAddressStr != null) {
                 Ip4Address ipAddress = Ip4Address.valueOf(ipAddressStr);
                 fixedIpMap.put(subnetId, ipAddress);
             }