Failure here: https://mci.10gen.com/ui/task/mongodb_mongo_master_linux_64_049f439ea3c8153d3f46663462c70bdf8f1fb602_13_11_06_16_41_05_sharding_linux_64

this looks like potentially a dupe of SERVER-9539 but filing anyway until we can be sure.

the failure did not occur on the other linux-64 builders and also did not occur on the following commit, so could be a flaky test behavior?