pyln-testing: close log files when tearing down node_factory

TailableProc has a cleanup_files() method to close its log files. Call
it when tearing down node_factory to avoid leaking resources.

Changelog-None

Author: whitslack

contrib/pyln-testing/pyln/testing/fixtures.py

@@ -512,6 +512,9 @@ def map_node_error(nodes, f, msg):
     if not ok:
         map_node_error(nf.nodes, prinErrlog, "some node failed unexpected, non-empty errlog file")
 
+    for n in nf.nodes:
+        n.daemon.cleanup_files()
+
 
 def getErrlog(node):
     for error_file in os.listdir(node.daemon.lightning_dir):