Remove unneeded OpenJDK fix from Travis CI configuration.
Remove unneeded OpenJDK fix from Travis CI configuration.

+ Resolves:
  java.net.UnknownHostException: short-hostname: short-hostname:
  Name or service not known
  > short-hostname: short-hostname: Name or service not known

EventFahrplan/EventFahrplan,EventFahrplan/EventFahrplan