Resolve a minor issue in expectation from Spec to Api

src/main/java/com/bryanjswift/simplenote/net/SimplenoteApi.java

@@ -166,7 +166,7 @@ public ApiResponse<Credentials> login(final String email, final String password)
         if (response.status == HttpStatus.SC_OK) {
             result = new ApiResponse<Credentials>(response.status, new Credentials(response.payload, email), response.headers);
         } else {
-            result = new ApiResponse<Credentials>(response.status, null, response.headers);
+            result = new ApiResponse<Credentials>(response.status, new Credentials(null, email, password), response.headers);
         }
         return result;
     }

src/test/scala/SimplenoteApiSpec.scala

@@ -27,7 +27,8 @@ class SimplenoteApiSpec extends WordSpec with ShouldMatchers {
       val response = unauthorized.login(badCredentials.email, badCredentials.password)
       response.status should not be (HttpStatus.SC_UNAUTHORIZED)
       response.payload.email should be (badCredentials.email)
-      response.payload.password should be (null)
+      response.payload.password should be (badCredentials.password)
+      response.payload should be (badCredentials)
     }
   }