avoid transient changes to MastershipStore from being posted as events

Change-Id: Id033cf50f865e44439138f5b3814ebaedb832b73
diff --git a/web/api/src/main/java/org/onlab/onos/rest/ConfigProvider.java b/web/api/src/main/java/org/onlab/onos/rest/ConfigProvider.java
index f560c83..08e3546 100644
--- a/web/api/src/main/java/org/onlab/onos/rest/ConfigProvider.java
+++ b/web/api/src/main/java/org/onlab/onos/rest/ConfigProvider.java
@@ -226,4 +226,9 @@
     public ProviderId id() {
         return PID;
     }
+
+    @Override
+    public boolean isReachable(Device device) {
+        return false;
+    }
 }