Backporting fix from d6eefa73e77632481c77ed2cd204940d56c1fca0

Issue https://github.com/jetty-project/jetty-alpn/issues/5 was fixed only for the latest code.  alpn-boot versions are tightly coupled to JDK versions, and so anyone not using the latest JDK version will not get the benefits of the fix.  It would be nice to maintain a branch pre jdk8_u25-b17 specifically for alpn-boot issues to account for this scenario.