CORD-333 Minimized OVSDB provider dependency

With this patch, cordvtn doesn't need to care for OVSDB connection state
anymore. It will make a connection to OVSDB server like befor but just
for node init and disconnect the OVSDB right after init is done.
- Changed OvsdbNode to CordVtnNode
- Removed OVSDB connect/disconnect and added initNode instead
- Changed ovsdb* commands to cordvtn-node* command, and removed
  connect/disconnect command and added init instead
- Fixed to remove OVSDB device from the system after node init or before
  making a connection to work around OVSDB device re-connect issue

Change-Id: If69369a06526947122494b2f7e816e37aa931f2c
diff --git a/src/main/java/org/onosproject/cordvtn/CordVtnConfigManager.java b/src/main/java/org/onosproject/cordvtn/CordVtnConfigManager.java
index 274ca9b..f79b446 100644
--- a/src/main/java/org/onosproject/cordvtn/CordVtnConfigManager.java
+++ b/src/main/java/org/onosproject/cordvtn/CordVtnConfigManager.java
@@ -88,10 +88,10 @@
             return;
         }
 
-        config.ovsdbNodes().forEach(node -> {
-            DefaultOvsdbNode ovsdb = new DefaultOvsdbNode(
-                    node.host(), node.ip(), node.port(), node.bridgeId());
-            cordVtnService.addNode(ovsdb);
+        config.cordVtnNodes().forEach(node -> {
+            CordVtnNode cordVtnNode = new CordVtnNode(
+                    node.hostname(), node.ovsdbIp(), node.ovsdbPort(), node.bridgeId());
+            cordVtnService.addNode(cordVtnNode);
         });
     }