In Karaf 4.2, dynamic service injections must be  declared as volatile

Change-Id: I4eb90b7364b7bc436280e4f0f2c71c3e83d86554
diff --git a/core/net/src/main/java/org/onosproject/net/intent/impl/ObjectiveTracker.java b/core/net/src/main/java/org/onosproject/net/intent/impl/ObjectiveTracker.java
index 288308d..eb01910 100644
--- a/core/net/src/main/java/org/onosproject/net/intent/impl/ObjectiveTracker.java
+++ b/core/net/src/main/java/org/onosproject/net/intent/impl/ObjectiveTracker.java
@@ -112,7 +112,7 @@
                 bind = "bindComponentConfigService",
                 unbind = "unbindComponentConfigService",
                 policy = ReferencePolicy.DYNAMIC)
-    protected IntentService intentService;
+    protected volatile IntentService intentService;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY)
     protected WorkPartitionService partitionService;