Refactor transaction support in preparation for migration to latest APIs
 - Added a explicit transaction id type
 - cli command now just returns the identifiers of in-progress transactions
 - Removed redriveTransactions until a better alternative is provided
 - Removed DatabaseUpdate and replaced its usage with MapUpdate

Change-Id: Ic4a14967072068834510cd8459fd2a6790e456ef
diff --git a/core/api/src/main/java/org/onosproject/store/service/DistributedPrimitive.java b/core/api/src/main/java/org/onosproject/store/service/DistributedPrimitive.java
index abdb14d..09d2979 100644
--- a/core/api/src/main/java/org/onosproject/store/service/DistributedPrimitive.java
+++ b/core/api/src/main/java/org/onosproject/store/service/DistributedPrimitive.java
@@ -61,7 +61,12 @@
         /**
          * Leader elector.
          */
-        LEADER_ELECTOR
+        LEADER_ELECTOR,
+
+        /**
+         * Transaction Context.
+         */
+        TRANSACTION_CONTEXT
     }
 
     static final long DEFAULT_OPERTATION_TIMEOUT_MILLIS = 5000L;