Switch to using -headless JDK

By default, jdks bring a bunch of UI related things
we don't need, so switch to headeless.

Also, use default-jdk-headless for Ubuntu after 14.04.
Use openjdk-8-jdk-headless for Ubuntu 14.04.

Change-Id: I3cf14c39c9f59dc2f1beba8dfb19971f4b67f5a6
Signed-off-by: Ed Warnicke <eaw@cisco.com>
1 file changed