Started happening since 24 hours ago.
http://buildlogs.mongodb.org/Nightly%20Linux%2064-bit%20C%2B%2B11%20Subscription%20Ubuntu%201204/builds/104/test/sharding/sort1.js
http://buildlogs.mongodb.org/Nightly%20OS%20X%2064-bit%2010.7%20C%2B%2B11%20DEBUG%20Subscription/builds/96/test/sharding/sort1.js
http://buildlogs.mongodb.org/Nightly%20Linux%2064-bit%20Subscription%20RHEL%205.7/builds/403/test/sharding/sort1.js
http://buildlogs.mongodb.org/Nightly%20Linux%2064-bit%20Subscription%20Ubuntu%201204/builds/98/test/sharding/sort1.js