Fix for JIRA ONOS-4620. Whenever networkconfiguration is deleted even the queued will be removed

Change-Id: I8d7f1a873af90cf86ea34f1a2b1585ef4c3e46e4
diff --git a/core/store/dist/src/main/java/org/onosproject/store/config/impl/DistributedNetworkConfigStore.java b/core/store/dist/src/main/java/org/onosproject/store/config/impl/DistributedNetworkConfigStore.java
index 87148a8..7a812c9 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/config/impl/DistributedNetworkConfigStore.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/config/impl/DistributedNetworkConfigStore.java
@@ -284,6 +284,24 @@
         configs.remove(key(subject, configKey));
     }
 
+    @Override
+    public <S> void clearConfig(S subject) {
+        ImmutableSet.copyOf(configs.keySet()).forEach(k -> {
+            if (Objects.equals(subject, k.subject) && delegate != null) {
+                configs.remove(k);
+            }
+        });
+    }
+
+    @Override
+    public <S> void clearConfig() {
+        ImmutableSet.copyOf(configs.keySet()).forEach(k -> {
+            if (delegate != null) {
+                configs.remove(k);
+            }
+        });
+    }
+
     /**
      * Produces a config from the specified subject, config class and raw JSON.
      *