VersionsTest.testCheckout to assert the VersionSeriesId equals previosly document created with pwc one.

The patch is:
— src/main/java/org/apache/chemistry/tck/atompub/test/spec/VersionsTest.java (revision 915741)
+++ src/main/java/org/apache/chemistry/tck/atompub/test/spec/VersionsTest.java (working copy)
@@ -101,7 +101,7 @@
CMISObject pwcObject = pwc.getExtension(CMISConstants.OBJECT);
Assert.assertNotNull(pwcObject);
Assert.assertTrue(pwcObject.isVersionSeriesCheckedOut().getBooleanValue());

• Assert.assertEquals(docObject.getObjectId().getStringValue(), pwcObject.getVersionSeriesId().getStringValue());
  + Assert.assertEquals(docObject.getVersionSeriesId().getStringValue(), pwcObject.getVersionSeriesId().getStringValue());
  Assert.assertEquals(pwcObject.getObjectId().getStringValue(), pwcObject.getVersionSeriesCheckedOutId().getStringValue());
  Assert.assertNotNull(pwcObject.getVersionSeriesCheckedOutBy().getStringValue());