Use try-with-resource to close resources in BundleWriter

Change-Id: I5341973737f6d21c04982bcbefc2ed672ac9bcff
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit/src/org/eclipse/jgit/transport/BundleWriter.java

@@ -194,8 +194,7 @@ public class BundleWriter {
 		PackConfig pc = packConfig;
 		if (pc == null)
 			pc = new PackConfig(db);
-		PackWriter packWriter = new PackWriter(pc, db.newObjectReader());
-		try {
+		try (PackWriter packWriter = new PackWriter(pc, db.newObjectReader())) {
 			final HashSet<ObjectId> inc = new HashSet<ObjectId>();
 			final HashSet<ObjectId> exc = new HashSet<ObjectId>();
 			inc.addAll(include.values());
@@ -233,8 +232,6 @@ public class BundleWriter {
 			w.write('\n');
 			w.flush();
 			packWriter.writePack(monitor, monitor, os);
-		} finally {
-			packWriter.release();
 		}
 	}
 }