[midPoint-git] [Evolveum/midpoint] b4ad0e: Fix change listeners potential concurrency issue

[mederly]

  Branch: refs/heads/master
  Home:   https://github.com/Evolveum/midpoint
  Commit: b4ad0ef35750c675c0df492341284d3da746b701
      https://github.com/Evolveum/midpoint/commit/b4ad0ef35750c675c0df492341284d3da746b701
  Author: Pavol Mederly <mederly at evolveum.com>
  Date:   2019-04-12 (Fri, 12 Apr 2019)

  Changed paths:
    M provisioning/provisioning-impl/src/main/java/com/evolveum/midpoint/provisioning/impl/ChangeNotificationDispatcherImpl.java

  Log Message:
  -----------
  Fix change listeners potential concurrency issue

Sometimes, the listener is null although seemingly it could never
happen. This is an attempt to avoid it.