Removed unnecessary DefaultLoggerFactory inner class from DefaultConfig

Fixed license header in LoggerFactory.java (via gradle licenseForamat)

src/main/java/net/schmizz/sshj/DefaultConfig.java

@@ -85,24 +85,6 @@ public class DefaultConfig
         setKeepAliveProvider(KeepAliveProvider.HEARTBEAT);
     }
 
-    /**
-     * Default SLF4J-based implementation of the SSHJ LoggerFactory.
-     */
-    public static class DefaultLoggerFactory implements LoggerFactory {
-        private DefaultLoggerFactory() {
-        }
-
-        @Override
-        public Logger getLogger(String name) {
-            return org.slf4j.LoggerFactory.getLogger(name);
-        }
-
-        @Override
-        public Logger getLogger(Class<?> clazz) {
-            return org.slf4j.LoggerFactory.getLogger(clazz);
-        }
-    }
-
     @Override
     public void setLoggerFactory(LoggerFactory loggerFactory) {
 	super.setLoggerFactory(loggerFactory);

src/main/java/net/schmizz/sshj/common/LoggerFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (C)2016 - SSHJ Contributors
+ * Copyright (C)2009 - SSHJ Contributors
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.