This commit harmonizes `LockRegistry#obtain` logic in Zookeeper and JDBC
implementations with Redis implementation
by using Java 8 `ConcurrentMap#computeIfAbsent`
* Remove `synchronized (this.locks)` from the `expireUnusedOlderThan`
implementations because `iterator()` is thread-safe from `ConcurrentHashMap`
* Fix deprecation in the `IntegrationGraphControllerRegistrar`
* Revert Spring Security version to `4.2.2`, since `5.0 B-S` is broken