SERVER-15269 Move Lock manager queue management to a separate class
SERVER-15269 Make Global and Flush lock requests jump the queue

The S and X modes on the Global and Flush locks are used for servicing
functions such as shutdown or replication step-down. Those should be
blocked minimally, so they should be able to get the lock with preference.
SERVER-15884 Clean up mongod --version output
Merge remote-tracking branch 'upstream/master'