Revert "add [openjdk11] to Travis build matrix (#586)" (#587)
Revert "add [openjdk11] to Travis build matrix (#586)" (#587)

This reverts commit 05a99a1c96c7a0ab5fb100cbf924efc7d808ce69.
ReactiveSocket/reactivesocket-java,rsocket/rsocket-java,ReactiveSocket/reactivesocket-java