All tests passing, but dbhash of collections on master not matching same slave collections.

Multiple examples, e.g.,
https://mci.10gen.com/ui/task/mongodb_mongo_master_linux_64_791e4d4b5d614ed13cc3eb67369aee83219d5baa_13_11_10_19_06_06_js_small_oplog_linux_64

[2013/11/10 22:01:20.493] The following collections has different hashes in master and slave
[2013/11/10 22:01:20.493] at the end of testing:
[2013/11/10 22:01:20.493] collection: jstests_remove9 (master/slave)
[2013/11/10 22:01:20.498] collection: jstests_shellspawn (master/slave)
[2013/11/10 22:01:20.500] collection: jstests_distinct3 (master/slave)