[ONOS-7068] Upgrade to Atomix 2.0.4

Change-Id: I864567084b1ac230254533026f06d4a25e5e0a2d
diff --git a/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/RaftMessageContext.java b/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/RaftMessageContext.java
index 2aecd0b..9f1f1bc 100644
--- a/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/RaftMessageContext.java
+++ b/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/RaftMessageContext.java
@@ -22,6 +22,7 @@
  */
 final class RaftMessageContext {
     private final String prefix;
+    final MessageSubject heartbeatSubject;
     final MessageSubject openSessionSubject;
     final MessageSubject closeSessionSubject;
     final MessageSubject keepAliveSubject;
@@ -40,6 +41,7 @@
 
     RaftMessageContext(String prefix) {
         this.prefix = prefix;
+        this.heartbeatSubject = getSubject(prefix, "heartbeat");
         this.openSessionSubject = getSubject(prefix, "open");
         this.closeSessionSubject = getSubject(prefix, "close");
         this.keepAliveSubject = getSubject(prefix, "keep-alive");