SERVER-15662 Reenable test that used to fail due to race condition.
SERVER-15740 Do not transition from RS_STARTUP to RS_REMOVED directly.

If a node is in RS_STARTUP (because it has no replica set configuration) and it learns of a
configuration that does not contain it, the correct behavior is to ignore the new configuration and
stay in RS_STARTUP, not to save the new configuration and enter RS_REMOVED.