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

UT failures: https://builds.apache.org/job/Ambari-branch-1.7.0/123/

This reverts commit 7d86ffc97a5b2e8ca0fe031b2cab662b2558971c.
Revert "AMBARI-7822. Events with Service Checks results in Exceptions in log."

UT failures: https://builds.apache.org/job/Ambari-branch-1.7.0/123/

This reverts commit f93722d0a684407a9c5c8451215ebb34ab0da852.