Fix integer boxing eclipse warning

Change-Id: I89a8495a799254586016393e51697cfbceacac8b
Signed-off-by: Hugo Arès <hugo.ares@ericsson.com>

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

@@ -609,7 +609,7 @@ public class StashApplyCommandTest extends RepositoryTestCase {
 		} catch (JGitInternalException e) {
 			assertEquals(MessageFormat.format(
 					JGitText.get().stashCommitIncorrectNumberOfParents,
-					head.name(), 0),
+					head.name(), "0"),
 					e.getMessage());
 		}
 	}