CORD-160 Add connect and disconnect methods to ovsdb

Change-Id: I66e777f8ec9c5834e27b1dc685fdeb197e30ce0d
diff --git a/ovsdb/api/src/main/java/org/onosproject/ovsdb/controller/OvsdbClientService.java b/ovsdb/api/src/main/java/org/onosproject/ovsdb/controller/OvsdbClientService.java
index ab88a24..c5f2092 100644
--- a/ovsdb/api/src/main/java/org/onosproject/ovsdb/controller/OvsdbClientService.java
+++ b/ovsdb/api/src/main/java/org/onosproject/ovsdb/controller/OvsdbClientService.java
@@ -228,4 +228,9 @@
      * @return ovsdb ports
      */
     Set<OvsdbPort> getLocalPorts(Iterable<String> ifaceids);
+
+    /**
+     * Disconnects the ovsdb server.
+     */
+    void disconnect();
 }