Coverity issue in contrail-controller/ovsdb_client_connection_state.cc

I have run Coverity on branch R5.0 and it reported the
following issue in
contrail-controller/ovsdb_client_connection_state.cc:PhysicalDeviceNotify()

deref_after_free: Dereferencing freed pointer state

Solution is to check if state!= NULL in:
"if (state->ha_stale_dev_vn_table_ != NULL) {".

Change-Id: Iafcf498adde07483af059d2302b9101d4fe860e4
Closes-Bug: #1777411
Signed-off-by: Anda Nicolae <anicolae@lenovo.com>

src/vnsw/agent/ovs_tor_agent/ovsdb_client/ovsdb_client_connection_state.cc

@@ -129,7 +129,7 @@ void ConnectionStateTable::PhysicalDeviceNotify(DBTablePartBase *part,
             }
             dev->ClearState(table_, id_);
 
-            if (state->ha_stale_dev_vn_table_ != NULL) {
+            if (state && state->ha_stale_dev_vn_table_ != NULL) {
                 state->ha_stale_dev_vn_table_->DeleteTable();
                 state->ha_stale_dev_vn_table_ = NULL;
             }