tests: Call reservebalance to trigger WakeThreadStakeMiner

Node 0 needs a short advantage to stake the first few blocks to avoid prevout-not-found errors.

tests/basicswap/extended/test_pivx.py

@@ -317,6 +317,8 @@ class Test(unittest.TestCase):
                 rpc('rescanblockchain')
             else:
                 rpc('extkeyimportmaster', [rpc('mnemonic', ['new'])['master']])
+            rpc('walletsettings', ['stakingoptions', {'stakecombinethreshold': 100, 'stakesplitthreshold': 200}])
+            rpc('reservebalance', [False])
 
             basicswap_dir = os.path.join(os.path.join(cfg.TEST_DATADIRS, str(i)), 'basicswap')
             settings_path = os.path.join(basicswap_dir, cfg.CONFIG_FILENAME)