More fixes for module mode

[dmlloyd]

Fixes a problem where the annotation processor cannot be instantiated in a modular application. Also fixes this exception which occurs in module mode:

java.lang.NullPointerException: Cannot invoke "javax.lang.model.element.ModuleElement.getClass()" because "module" is null
  	at jdk.compiler/com.sun.tools.javac.model.JavacElements.getTypeElement(JavacElements.java:167)
  	at jdk.compiler/com.sun.tools.javac.model.JavacElements.getTypeElement(JavacElements.java:88)
  	at org.jboss.logging.processor.apt.MessageInterfaceFactory$AptMessageInterface.<init>(MessageInterfaceFactory.java:146)
  	at org.jboss.logging.processor.apt.MessageInterfaceFactory.of(MessageInterfaceFactory.java:98)
  	at org.jboss.logging.processor.apt.LoggingToolsProcessor.doProcess(LoggingToolsProcessor.java:200)
  	at org.jboss.logging.processor.apt.LoggingToolsProcessor.process(LoggingToolsProcessor.java:165)
  	(...)