Classes overriding `preRestart` should be able to call `super.preRestart` as shown in [this example](https://github.com/eligosource/akka/blob/wip-3618-cleanup-lifecycle-hooks-krasserm/akka-samples/akka-sample-persistence/src/main/scala/sample/persistence/ProcessorFailureExample.scala#L21) (first delete message then run recovery as defined in `Processor.preRestart`). A subclass calling `super.preRestart` will only call `Processor.preRestart` whereas the `super.preRestart` call in `preRestartDefault` calls `Stash.preRestart`  as it should be. No duplicate call of any `preRestart` definition.