Revert "AMBARI-7822. Events with Service Checks results in Exceptions in log. Null check."

UT fails: https://builds.apache.org/view/All/job/Ambari-trunk-Commit/613/

This reverts commit 43ab9e61f076affb0a6fc92e39053cf0e8b6d163.
Revert "AMBARI-7822. Events with Service Checks results in Exceptions in log."

UT failures: https://builds.apache.org/view/All/job/Ambari-trunk-Commit/613/

This reverts commit 383d3e7116565fba181ec823c455867a99ff09e3.