Change vlsd's RPC URL arg to --bitcoin

Author: ksedgwic

contrib/pyln-testing/pyln/testing/utils.py

@@ -630,7 +630,7 @@ def __init__(self, vlsd_dir, vlsd_port, node_id, network):
             '--port={}'.format(vlsd_port),
             '--initial-allowlist-file={}'.format(env('REMOTE_SIGNER_ALLOWLIST',
                                                      'contrib/remote_hsmd/TESTING_ALLOWLIST')),
-            '--rpc=http://{}:{}@127.0.0.1:{}'.format(
+            '--bitcoin=http://{}:{}@127.0.0.1:{}'.format(
                 BITCOIND_CONFIG['rpcuser'],
                 BITCOIND_CONFIG['rpcpassword'],
                 BITCOIND_CONFIG['rpcport']),