tests: allow failure on python nightly

ploxiln · ploxiln · commit ecd42b610d88 · 2019-06-08T15:18:08.000-04:00
seems to be due to a bunch of asyncio.exceptions.CancelledError
diff --git a/.travis.yml b/.travis.yml
@@ -4,6 +4,8 @@ dist: xenial
 language: python
 matrix:
     fast_finish: true
+    allow_failures:
+      - python: nightly
 addons:
   apt: 
     packages:
