try llfuse on py39

there was a fixed llfuse release today, so lets try it!

.travis.yml

@@ -30,11 +30,11 @@ matrix:
         - python: "3.9-dev"
           os: linux
           dist: xenial
-          env: TOXENV=py39 SKIPFUSE=true
+          env: TOXENV=py39
         - python: "3.9-dev"
           os: linux
           dist: focal
-          env: TOXENV=py39 SKIPFUSE=true
+          env: TOXENV=py39
         - python: "3.6"
           os: linux
           dist: xenial