SEC-633: Handle null credentials in AbstractAuthenticationToken.equals

Also added a test for the OpenIDAuthenticationToken to reproduce the original error.

sandbox/openid/src/test/java/org/springframework/security/providers/openid/OpenIdAuthenticationTokenTests.java

@@ -0,0 +1,25 @@
+package org.springframework.security.providers.openid;
+
+import junit.framework.TestCase;
+
+/**
+ * DOCUMENT ME!
+ *
+ * @author Ray Krueger
+ */
+public class OpenIdAuthenticationTokenTests extends TestCase {
+
+    public void test() throws Exception {
+        OpenIDAuthenticationToken token = newToken();
+        assertEquals(token, newToken());
+    }
+
+    private OpenIDAuthenticationToken newToken() {
+        return new OpenIDAuthenticationToken(
+                OpenIDAuthenticationStatus.SUCCESS,
+                "http://raykrueger.blogspot.com/",
+                "what is this for anyway?");
+    }
+
+
+}