Merge pull request #305 from reactive-streams/wip-unbreak-travisci-√

Unbreaks TravisCI OpenJDK6 hostname too long crash

Author: viktorklang

Diff for: .travis.yml

@@ -12,3 +12,6 @@ env:
   - TERM=dumb
   - DEFAULT_TIMEOUT_MILLIS=300
   - PUBLISHER_REFERENCE_GC_TIMEOUT_MILLIS=300
+addons:
+  # Fix OpenJDK build. Issue: https://github.com/travis-ci/travis-ci/issues/5227 & https://docs.travis-ci.com/user/hostname
+  hostname: short-hostname