Use getPath() in FileResolverTest

Necessary to get tests to pass when running under Buck.
Has no impact on Maven based invocation of tests.

Change-Id: I437114863df0bac346c94ef13796def47333d916

org.eclipse.jgit.http.test/tst/org/eclipse/jgit/http/test/FileResolverTest.java

@@ -153,7 +153,7 @@ public class FileResolverTest extends LocalDiskRepositoryTestCase {
 			Throwable why = e.getCause();
 			assertNotNull("has cause", why);
 			assertEquals("repository not found: "
-					+ new File(base, name).getAbsolutePath(), why.getMessage());
+					+ new File(base, name).getPath(), why.getMessage());
 		}
 	}
 }