mod_pubsub_feeds: Retrieve only the most recent item to compare Only need one item id. Fetching all items probably caused memory usage peaks.

2c07bcf56a36d6e74dc0f5422e89bd61f4d31239 0.8-diverge
1656d4fd71d07aa3a52da89d4daf7723a555e7dd last-google-code-commit