Configure OVSDB to either run as hybrid mode or client mode

With current implementation, OVSDB is always running as hybrid
mode which is running both server and client.
In case, ONOS and OVS run in the same machine, we encounter
port conflict issues. To resolve this issue, we would like to
add a configurable parameter to enforce ONOS only runs as OVSDB
client without listening port 6640. Note that, by default ONOS
will be still running as hybrid mode.

Change-Id: I8c1d310335c0a0a661e9011905c00456baec309f
diff --git a/providers/ovsdb/device/src/test/java/org/onosproject/ovsdb/providers/device/OvsdbDeviceProviderTest.java b/providers/ovsdb/device/src/test/java/org/onosproject/ovsdb/providers/device/OvsdbDeviceProviderTest.java
index ec0bba6..eff79bf 100644
--- a/providers/ovsdb/device/src/test/java/org/onosproject/ovsdb/providers/device/OvsdbDeviceProviderTest.java
+++ b/providers/ovsdb/device/src/test/java/org/onosproject/ovsdb/providers/device/OvsdbDeviceProviderTest.java
@@ -258,6 +258,11 @@
 
         }
 
+        @Override
+        public void setServerMode(boolean serverMode) {
+
+        }
+
     }
 
     private class TestDeviceService extends DeviceServiceAdapter {
diff --git a/providers/ovsdb/host/src/test/java/org/onosproject/ovsdb/provider/host/OvsdbHostProviderTest.java b/providers/ovsdb/host/src/test/java/org/onosproject/ovsdb/provider/host/OvsdbHostProviderTest.java
index ea15ad2..ae58c20 100644
--- a/providers/ovsdb/host/src/test/java/org/onosproject/ovsdb/provider/host/OvsdbHostProviderTest.java
+++ b/providers/ovsdb/host/src/test/java/org/onosproject/ovsdb/provider/host/OvsdbHostProviderTest.java
@@ -218,5 +218,10 @@
         public void connect(IpAddress ip, TpPort port, Consumer<Exception> failhandler) {
 
         }
+
+        @Override
+        public void setServerMode(boolean serverMode) {
+
+        }
     }
 }