Use property constants for OSGi components for stores

Change-Id: I5d21075abb453d5bc54e02653d5a96746e6a074e
diff --git a/core/store/dist/src/main/java/org/onosproject/store/statistic/impl/DistributedStatisticStore.java b/core/store/dist/src/main/java/org/onosproject/store/statistic/impl/DistributedStatisticStore.java
index c4a7f19..d9902fe 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/statistic/impl/DistributedStatisticStore.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/statistic/impl/DistributedStatisticStore.java
@@ -59,6 +59,8 @@
 import static java.util.concurrent.Executors.newFixedThreadPool;
 import static org.onlab.util.Tools.get;
 import static org.onlab.util.Tools.groupedThreads;
+import static org.onosproject.store.OsgiPropertyConstants.DSS_MESSAGE_HANDLER_THREAD_POOL_SIZE;
+import static org.onosproject.store.OsgiPropertyConstants.DSS_MESSAGE_HANDLER_THREAD_POOL_SIZE_DEFAULT;
 import static org.slf4j.LoggerFactory.getLogger;
 
 
@@ -66,7 +68,13 @@
  * Maintains statistics using RPC calls to collect stats from remote instances
  * on demand.
  */
-@Component(immediate = true, service = StatisticStore.class)
+@Component(
+        immediate = true,
+        service = StatisticStore.class,
+        property = {
+                DSS_MESSAGE_HANDLER_THREAD_POOL_SIZE + "=" + DSS_MESSAGE_HANDLER_THREAD_POOL_SIZE_DEFAULT
+        }
+)
 public class DistributedStatisticStore implements StatisticStore {
 
     private final Logger log = getLogger(getClass());
@@ -101,10 +109,9 @@
 
     private ExecutorService messageHandlingExecutor;
 
-    private static final int DEFAULT_MESSAGE_HANDLER_THREAD_POOL_SIZE = 4;
     //@Property(name = "messageHandlerThreadPoolSize", intValue = DEFAULT_MESSAGE_HANDLER_THREAD_POOL_SIZE,
     //        label = "Size of thread pool to assign message handler")
-    private static int messageHandlerThreadPoolSize = DEFAULT_MESSAGE_HANDLER_THREAD_POOL_SIZE;
+    private static int messageHandlerThreadPoolSize = DSS_MESSAGE_HANDLER_THREAD_POOL_SIZE_DEFAULT;
 
     private static final long STATISTIC_STORE_TIMEOUT_MILLIS = 3000;