test_lightningd: rename has_failed to allow_failure.

Note that it should really be a flag to daemon on construction, too,
but that may interfere with another concurrent branch so I've deferred.

Suggested-by: Christian Decker
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

tests/utils.py

@@ -310,7 +310,8 @@ class LightningNode(object):
         db.close()
         return result
 
-    def has_failed(self):
+    # FIXME: we should flag daemon on startup, suppress error
+    def allow_failure(self):
         """Note that a daemon has (deliberately) crashed, so we don't fail
         on cleanup"""
         self.known_fail = True