Adds retry logic around various other errors we've received during shutd...

...owns of secondaries for maintenance and stepdowns on a mongos cluster behind a load-balancer.

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We have our mongoid.yml point to a single load balancer address for our mongos setup. We have done routine maintenance such as remove secondaries for compaction and stepDowns and these are the errors we've seen in our code that have been uncaught exceptions coming from Moped:

15988 ("error querying server")
10276 ("DBClientBase::findN: transport error:" to a shard)
11600 ("interrupted at shutdown")
10009 ("ReplicaSetMonitor no master found for set")

I'm adding these to raise either or ConnectionFailure or ReplicaSetReconfigured error, which will cause a retry to occur.