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.

server.go

@@ -108,7 +108,7 @@ func newServer(listenAddrs []string, notifier chainntnfs.ChainNotifier,
 		chanDB:        chanDB,
 
 		invoices:    newInvoiceRegistry(chanDB),
-		utxoNursery: newUtxoNursery(notifier, wallet),
+		utxoNursery: newUtxoNursery(chanDB, notifier, wallet),
 		htlcSwitch:  newHtlcSwitch(),
 
 		identityPriv: privKey,