expose CBlockIndex::nTx in getblock(header)

test/functional/rpc_blockchain.py

@@ -217,6 +217,7 @@ class BlockchainTest(BitcoinTestFramework):
         assert_equal(header['confirmations'], 1)
         assert_equal(header['previousblockhash'], secondbesthash)
         assert_is_hex_string(header['chainwork'])
+        assert_equal(header['nTx'], 1)
         assert_is_hash_string(header['hash'])
         assert_is_hash_string(header['previousblockhash'])
         assert_is_hash_string(header['merkleroot'])