No longer allow amazonlinux to fail

.travis.yml

@@ -8,10 +8,6 @@ env:
   - SCENARIO=centos
   - SCENARIO=fedora
   - SCENARIO=amazonlinux
-matrix:
-  fast_finish: true
-  allow_failures:
-    - env: SCENARIO=amazonlinux  # https://github.com/inspec/train/pull/312
 services: docker
 addons:
   apt: