RPC tests: fixes merkle_blocks.py to exclude 1st coinbase (#423)

* fixes merkle_blocks.py to exclude 1st coinbase

* Update qa/rpc-tests/merkle_blocks.py

Co-Authored-By: marcus290 <36244342+marcus290@users.noreply.github.com>

Author: marcus290

qa/rpc-tests/merkle_blocks.py

@@ -41,7 +41,7 @@ def run_test(self):
         assert_equal(self.nodes[1].getbalance(), 0)
         assert_equal(self.nodes[2].getbalance(), 0)
 
-        node0utxos = self.nodes[0].listunspent(1)
+        node0utxos = self.nodes[0].listunspent(1, 104) // We generated 105 blocks so we are excluding the first block which contains 59 mill~ NAV
         tx1 = self.nodes[0].createrawtransaction([node0utxos.pop()], {self.nodes[1].getnewaddress(): 49.99})
         txid1 = self.nodes[0].sendrawtransaction(self.nodes[0].signrawtransaction(tx1)["hex"])
         tx2 = self.nodes[0].createrawtransaction([node0utxos.pop()], {self.nodes[1].getnewaddress(): 49.99})