SERVER-14442 Make ReplicationCoordinator responsible for constructing ReplSetUpdatePosition commands
SERVER-14550 Stop maintaining local.slaves
SERVER-14212 When restoring users and roles for a single db with --drop, don't drop users/roles from other databases
SERVER-14475 Cleanup the shutdown code and indicate shutdown earlier
SERVER-13961 Cleanup some nested instantiations of OperationContextImpl in repl

These are causing deadlocks if LockState is removed from TLS because of
pseudo-conflicting locks on the same code path.
SERVER-13961 Pass OperationContext into WhereCallbackReal

There are no functional changes in this commit, just preparation for the
subsequent one, which will add operation context to the JS execution
scope.
SERVER-14212 Fix test of _mergeAuthzCollections command by adding missing "db" field
SERVER-9790 SERVER-14554 (v8-3.25) Add this.$db || db.toString() to DBRef string representation