utxonursery: added persistence to transaction output states

Moved transaction states from in-memory maps to persistent BoltDB
buckets. This allows channel force closes to operate reliably if the
daemon is shut down and restarted at any point during the forced
channel closure process.

networktest.go

@@ -734,7 +734,7 @@ func (n *networkHarness) WaitForChannelOpen(ctx context.Context,
 // pending, then an error is returned.
 func (n *networkHarness) CloseChannel(ctx context.Context,
 	lnNode *lightningNode, cp *lnrpc.ChannelPoint,
-	force bool) (lnrpc.Lightning_CloseChannelClient, error) {
+	force bool) (lnrpc.Lightning_CloseChannelClient, *wire.ShaHash, error) {
 
 	closeReq := &lnrpc.CloseChannelRequest{
 		ChannelPoint: cp,
@@ -742,11 +742,11 @@ func (n *networkHarness) CloseChannel(ctx context.Context,
 	}
 	closeRespStream, err := lnNode.CloseChannel(ctx, closeReq)
 	if err != nil {
-		return nil, fmt.Errorf("unable to close channel: %v", err)
+		return nil, nil, fmt.Errorf("unable to close channel: %v", err)
 	}
 
 	errChan := make(chan error)
-	fin := make(chan struct{})
+	fin := make(chan *wire.ShaHash)
 	go func() {
 		// Consume the "channel close" update in order to wait for the closing
 		// transaction to be broadcast, then wait for the closing tx to be seen
@@ -772,20 +772,19 @@ func (n *networkHarness) CloseChannel(ctx context.Context,
 			errChan <- err
 			return
 		}
-
-		close(fin)
+		fin <- closeTxid
 	}()
 
 	// Wait until either the deadline for the context expires, an error
 	// occurs, or the channel close update is received.
 	select {
 	case <-ctx.Done():
-		return nil, fmt.Errorf("timeout reached before channel close " +
+		return nil, nil, fmt.Errorf("timeout reached before channel close " +
 			"initiated")
 	case err := <-errChan:
-		return nil, err
-	case <-fin:
-		return closeRespStream, nil
+		return nil, nil, err
+	case closeTxid := <-fin:
+		return closeRespStream, closeTxid, nil
 	}
 }