[error prone] fix ReferenceEquality warning in RefUpdate#updateImpl

Change-Id: I6687e1eec6b6ecfe319a598ef8aec1976cee354b
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit/src/org/eclipse/jgit/lib/RefUpdate.java

@@ -53,6 +53,7 @@ import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.revwalk.RevObject;
 import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.transport.PushCertificate;
+import org.eclipse.jgit.util.References;
 
 /**
  * Creates, updates or deletes any reference.
@@ -768,7 +769,8 @@ public abstract class RefUpdate {
 			}
 
 			oldObj = safeParseOld(walk, oldValue);
-			if (newObj == oldObj && !detachingSymbolicRef) {
+			if (References.isSameObject(newObj, oldObj)
+					&& !detachingSymbolicRef) {
 				return store.execute(Result.NO_CHANGE);
 			}