Revert JDK8 -> 7 change in Bazel Docker container
Revert JDK8 -> 7 change in Bazel Docker container

Summary: Kythe still has JDK8 jars checked-in for the Bazel tools.

Reviewers: zarko, shahms

Reviewed By: shahms

Differential Revision: https://phabricator-dot-kythe-repo.appspot.com/D373

kidaa/kythe,benjyw/kythe,legrosbuffle/kythe,benjyw/kythe,bowlofstew/kythe,kythe/kythe,bowlofstew/kythe,bzz/kythe,kythe/kythe,bowlofstew/kythe,benjyw/kythe,legrosbuffle/kythe,bzz/kythe,legrosbuffle/kythe,bowlofstew/kythe,benjyw/kythe,benjyw/kythe,kidaa/kythe,benjyw/kythe,bowlofstew/kythe,kythe/kythe,benjyw/kythe,bzz/kythe,kidaa/kythe,bowlofstew/kythe,kythe/kythe,benjyw/kythe,kidaa/kythe,bzz/kythe,kythe/kythe,kidaa/kythe,kidaa/kythe,bowlofstew/kythe,benjyw/kythe,legrosbuffle/kythe,kythe/kythe,bzz/kythe,bzz/kythe,bowlofstew/kythe,benjyw/kythe,legrosbuffle/kythe,bzz/kythe,kidaa/kythe,bowlofstew/kythe,kythe/kythe,bzz/kythe,legrosbuffle/kythe,bzz/kythe,kythe/kythe,bzz/kythe,benjyw/kythe,kythe/kythe,legrosbuffle/kythe,legrosbuffle/kythe,bzz/kythe,kythe/kythe,bowlofstew/kythe,legrosbuffle/kythe,bzz/kythe,legrosbuffle/kythe,benjyw/kythe,kidaa/kythe,legrosbuffle/kythe,kidaa/kythe,bowlofstew/kythe,kythe/kythe