Adding ability for Config to be backed by generic JsonNode, i.e. either ObjectNode or ArrayNode.

Change-Id: I5f9ec423cd5f23f61c97a57073d9d11071c47997
diff --git a/incubator/api/src/main/java/org/onosproject/incubator/net/config/basics/InterfaceConfig.java b/incubator/api/src/main/java/org/onosproject/incubator/net/config/basics/InterfaceConfig.java
index 600fe3d..acda179 100644
--- a/incubator/api/src/main/java/org/onosproject/incubator/net/config/basics/InterfaceConfig.java
+++ b/incubator/api/src/main/java/org/onosproject/incubator/net/config/basics/InterfaceConfig.java
@@ -50,7 +50,8 @@
         Set<Interface> interfaces = Sets.newHashSet();
 
         try {
-            for (JsonNode intfNode : node.path(INTERFACES)) {
+            // TODO: rework this to take advantage of ArrayNode backing
+            for (JsonNode intfNode : object.path(INTERFACES)) {
                 Set<InterfaceIpAddress> ips = getIps(intfNode);
                 if (ips.isEmpty()) {
                     throw new ConfigException(IP_MISSING_ERROR);