message: [net] Make cs_inventory a non-recursive mutex
  cs_inventory is never taken recursively. Make it a non-recursive mutex.
diff: @@ -810,7 +810,7 @@ public:
  // There is no final sorting before sending, as they are always sent immediately
  // and in the order requested.
  std::vector<uint256> vInventoryBlockToSend GUARDED_BY(cs_inventory);
  - RecursiveMutex cs_inventory;
  + Mutex cs_inventory;
  struct TxRelay {
  mutable RecursiveMutex cs_filter;
  