f - missing import for no-std

Author: jkczyz

lightning/src/chain/transaction.rs

@@ -13,6 +13,8 @@ use bitcoin::hash_types::Txid;
 use bitcoin::blockdata::transaction::OutPoint as BitcoinOutPoint;
 use bitcoin::blockdata::transaction::Transaction;
 
+use prelude::Vec;
+
 /// Transaction data where each item consists of a transaction reference paired with the index of
 /// the transaction within a block.
 ///