RevCommitListTest: Open Git and RevWalk in try-with-resource

Change-Id: I4ba273a364a12f82a3b3b06ba050bc633411daf6
Signed-off-by: David Pursehouse <david.pursehouse@sonymobile.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/revwalk/RevCommitListTest.java

@@ -57,15 +57,16 @@ public class RevCommitListTest extends RepositoryTestCase {
 	private RevCommitList<RevCommit> list;
 
 	public void setup(int count) throws Exception {
-		Git git = new Git(db);
+		try (Git git = new Git(db);
+				RevWalk w = new RevWalk(db);) {
 			for (int i = 0; i < count; i++)
 				git.commit().setCommitter(committer).setAuthor(author)
 						.setMessage("commit " + i).call();
 			list = new RevCommitList<RevCommit>();
-		RevWalk w = new RevWalk(db);
 			w.markStart(w.lookupCommit(db.resolve(Constants.HEAD)));
 			list.source(w);
 		}
+	}
 
 	@Test
 	public void testFillToHighMark2() throws Exception {
@@ -107,7 +108,7 @@ public class RevCommitListTest extends RepositoryTestCase {
 	public void testFillToCommit() throws Exception {
 		setup(3);
 
-		RevWalk w = new RevWalk(db);
+		try (RevWalk w = new RevWalk(db)) {
 			w.markStart(w.lookupCommit(db.resolve(Constants.HEAD)));
 
 			w.next();
@@ -119,6 +120,7 @@ public class RevCommitListTest extends RepositoryTestCase {
 			assertEquals("commit 1", list.get(1).getFullMessage());
 			assertNull(list.get(3));
 		}
+	}
 
 	@Test
 	public void testFillToUnknownCommit() throws Exception {