[SPARK-13642][Yarn][1.6-backport] Properly handle signal kill in ApplicationMaster#11690

jerryshao wants to merge 3 commits intoapache:branch-1.6apache/spark:branch-1.6from

jerryshao:SPARK-13642-1.6-backportjerryshao/apache-spark:SPARK-13642-1.6-backportCopy head branch name to clipboard