Make JPEGTurboServicImpl.logger transient

Otherwise, on deserialization the following exception is
thrown:

```
Exception in thread "Thread-14" java.lang.NullPointerException
    at java.util.logging.LogManager.access$900(LogManager.java:130)
    at java.util.logging.LogManager$RootLogger.getHandlers(LogManager.java:979)
    at java.util.logging.LogManager.resetLogger(LogManager.java:677)
    at java.util.logging.LogManager.reset(LogManager.java:665)
    at java.util.logging.LogManager$Cleaner.run(LogManager.java:223)
```