Update to Java8

[sreevatsanraman]

Build passes locally

[INFO]  system:cdap-data-pipeline[4.3.0-SNAPSHOT,9.0.0-SNAPSHOT)
[INFO] ------------------------------------------------------------------------
[WARNING] Skipping non JSON file 'condition-plugin.png'
[WARNING] Skipping non JSON file 'condition-plugin.sdxml'
[INFO] Successfully created  : condition-plugins-1.0.4.json
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ condition-plugins ---
[INFO] Building jar: /Users/sreevatsan/work/condition-plugins/target/condition-plugins-1.0.4.jar
[INFO] 
[INFO] --- maven-bundle-plugin:2.3.7:bundle (default) @ condition-plugins ---
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 19.091 s
[INFO] Finished at: 2018-07-19T07:03:20-07:00
[INFO] Final Memory: 44M/569M
[INFO] ------------------------------------------------------------------------

[sreevatsanraman]

JIRA: https://issues.cask.co/browse/CDAP-12787