Replace manual hash code calculation for long with Long.hashCode(long)

Change-Id: Ie588a2904e0fcc790282af22912e8ff6d7a31648
diff --git a/core/api/src/main/java/org/onosproject/net/intent/IntentId.java b/core/api/src/main/java/org/onosproject/net/intent/IntentId.java
index e2bf307..b3077c5 100644
--- a/core/api/src/main/java/org/onosproject/net/intent/IntentId.java
+++ b/core/api/src/main/java/org/onosproject/net/intent/IntentId.java
@@ -60,7 +60,7 @@
 
     @Override
     public int hashCode() {
-        return (int) (value ^ (value >>> 32));
+        return Long.hashCode(value);
     }
 
     @Override