Fixed ClassDefNotFound exception on weblogic when application is going for shutdown since classloader is already deactivated and does not load new classes anymore

Conflicts:
	hazelcast/src/main/java/com/hazelcast/spi/DistributedObjectAccessor.java
Removed import
Merge pull request #2391 from noctarius/fix-weblogic-shutdown-backport

Fix weblogic shutdown backport