Revert "SERVER-15557 disallow setting of configuration options for non-active storage engine"

This reverts commit cf1c4bb5a9da98ec831ff0a30ae78abe81e1d1b0.
SERVER-14462 Fix all cases where client is null when we are creating an
OperationContext
SERVER-14462 Make db.currentOp report the currently held locks from the Lock Manager
Merge remote-tracking branch 'root/master'