node/pkg/ethereum: reduce timeout for TransactionReceipt

We should spend as little time holding pendingMu as possible.
Ideally, we would refactor the component to do non-blocking I/O.

commit-id:b464c384

node/pkg/ethereum/watcher.go

@@ -313,7 +313,7 @@ func (e *Watcher) Run(ctx context.Context) error {
 
 					// Transaction is now ready
 					if pLock.height+uint64(expectedConfirmations) <= blockNumberU {
-						timeout, cancel = context.WithTimeout(ctx, 15*time.Second)
+						timeout, cancel = context.WithTimeout(ctx, 5*time.Second)
 						tx, err := c.TransactionReceipt(timeout, pLock.message.TxHash)
 						cancel()