Comment 4 for bug 1171714

To test:

1. Create a Mahara site with two RSS blocks in it
2. Point one block at a URL that will return a garbled RSS feed (this can be tricky to accomplish, because Mahara validates the RSS feed when you create the block. I found it easiest to update the url directly in the blocktype_externalfeed_data table)
3. Run the cron job to refresh both blocks (Again, this is tricky because the rss refresh_feeds task has some timing restrictions in it; I wound up editing the code to simplify the SQL so that it fetched every feed every time, and sorted them in order so that the good feed always came before the bad feed)

Actual result: If the bad RSS feed gets processed after the good RSS feed in the loop, it will be overwritten with the good RSS feed's data.

Expected result: Neither RSS feed should be overwritten by the other