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/Key.java b/core/api/src/main/java/org/onosproject/net/intent/Key.java
index dc9ef36..8420188 100644
--- a/core/api/src/main/java/org/onosproject/net/intent/Key.java
+++ b/core/api/src/main/java/org/onosproject/net/intent/Key.java
@@ -42,7 +42,7 @@
 
     @Override
     public int hashCode() {
-        return (int) (hash() ^ (hash() >>> 32));
+        return Long.hashCode(hash);
     }
 
     @Override