Removed the per-Nptpool and per Npstats locks. The srv->lock is used to protect these data structures now. Drop diod_flush () and libnpfs support for flushing ops in progress. tflush will only flush pending requests now. This elminates some complexity in libnpfs that wasn't being utilized in diod anyway. Drop Npconn reqs_in/rqs_out counters that introduced additional locking entanglements and wasn't really used for much.