Update junit runner to 1.0.15 to get java 7 compatibility
Review Request #4324 — Created Oct. 18, 2016 and submitted
|benjyw, jsirois, mateor, stuhood|
The junit-runner 1.0.15 jar should now be java 7 compatible.
Also set the platform of the scala and javac tool to java7 for the next time those are published.
Build green at https://travis-ci.org/pantsbuild/pants/builds/168588698
Also tested this jar in our Java repo under Java 7 and it works.