Adds a CLI to show/clear cached openstack states with neutron DB

Change-Id: I270c27affc669d10236ce94ec7a546a4f85aea88
diff --git a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/cli/OpenstackPortListCommand.java b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/cli/OpenstackPortListCommand.java
index e3398da..131c809 100644
--- a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/cli/OpenstackPortListCommand.java
+++ b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/cli/OpenstackPortListCommand.java
@@ -33,7 +33,6 @@
 import java.util.List;
 import java.util.stream.Collectors;
 
-import static org.onosproject.cli.AbstractShellCommand.get;
 import static org.onosproject.openstacknetworking.util.OpenstackNetworkingUtil.modelEntityToJson;
 import static org.onosproject.openstacknetworking.util.OpenstackNetworkingUtil.prettyJson;
 
@@ -71,8 +70,9 @@
                         .map(IP::getIpAddress)
                         .collect(Collectors.toList());
                 Network osNet = service.network(port.getNetworkId());
+                String netName = osNet == null ? "N/A" : osNet.getName();
                 print(FORMAT, port.getId(),
-                        osNet.getName(),
+                        netName,
                         port.getMacAddress(),
                         fixedIps.isEmpty() ? "" : fixedIps);
             }