DescribeCommandTest: Open FileWriter in try-with-resource

Change-Id: Ida79bdae652faa88fbdb1b81e7e10b5019ff2c16
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/api/DescribeCommandTest.java

@@ -297,9 +297,9 @@ public class DescribeCommandTest extends RepositoryTestCase {
 	}
 
 	private static void touch(File f, String contents) throws Exception {
-		FileWriter w = new FileWriter(f);
-		w.write(contents);
-		w.close();
+		try (FileWriter w = new FileWriter(f)) {
+			w.write(contents);
+		}
 	}
 
 	private String describe(ObjectId c1, boolean longDesc)