[ONOS-7381] Reset phi accrual failure detectors when nodes are re-activated

Change-Id: I283ef9daca8dedcc1260a7e5299f559ee7a1c6e0
diff --git a/core/store/dist/src/main/java/org/onosproject/store/cluster/impl/PhiAccrualFailureDetector.java b/core/store/dist/src/main/java/org/onosproject/store/cluster/impl/PhiAccrualFailureDetector.java
index 590946d..922057f 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/cluster/impl/PhiAccrualFailureDetector.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/cluster/impl/PhiAccrualFailureDetector.java
@@ -75,7 +75,14 @@
         }
     }
 
-
+    /**
+     * Resets the failure detector for the given node.
+     *
+     * @param nodeId node identifier for the node for which to reset the failure detector
+     */
+    public void reset(NodeId nodeId) {
+        states.put(nodeId, new History());
+    }
 
     /**
      * Compute phi for the specified node id.