zeppelin git commit: [Doc] Doc for LifecycleManager

Repository: zeppelin Updated Branches: refs/heads/master 2674291d6 -> d925e052a [Doc] Doc for LifecycleManager ### What is this PR for? Documentation for LifecycleManager ### What type of PR is it? [ Documentation ] ### Questions: * Does the licenses files need update? No * Is there breaking

zeppelin git commit: [ZEPPELIN-3017] fix Spark version in Dockerfiles

Repository: zeppelin Updated Branches: refs/heads/master 4054320a4 -> 2674291d6 [ZEPPELIN-3017] fix Spark version in Dockerfiles ### What is this PR for? The PR updates Spark version to the current 2.1.2, since the one which is present now (2.1.1) is not available anymore. ### What type of