Minor, fixed checkstyle and find bugs warns

broker/src/main/java/io/moquette/server/netty/AutoFlushHandler.java

@@ -111,7 +111,8 @@ public class AutoFlushHandler extends ChannelDuplexHandler {
         // Avoid the case where destroy() is called before scheduling timeouts.
         // See: https://github.com/netty/netty/issues/143
         if (LOG.isDebugEnabled()) {
-            LOG.debug("Initializing autoflush handler on channel {} Cid: {}", ctx.channel(), NettyUtils.clientID(ctx.channel()));
+            LOG.debug("Initializing autoflush handler on channel {} Cid: {}", ctx.channel(),
+                      NettyUtils.clientID(ctx.channel()));
         }
         switch (state) {
             case 1:

broker/src/main/java/io/moquette/server/netty/metrics/MQTTMessageLogger.java

@@ -60,7 +60,7 @@ public class MQTTMessageLogger extends ChannelDuplexHandler {
         }
         MqttMessage msg = (MqttMessage) message;
         if (msg.fixedHeader() == null) {
-        	throw new IOException("Unknown packet");
+            throw new IOException("Unknown packet");
         }
         String clientID = NettyUtils.clientID(ctx.channel());
         MqttMessageType messageType = msg.fixedHeader().messageType();
@@ -69,7 +69,7 @@ public class MQTTMessageLogger extends ChannelDuplexHandler {
             case PINGREQ:
             case PINGRESP:
                 LOG.debug("{} {} <{}>", direction, messageType, clientID);
-                break;        
+                break;
             case CONNECT:
             case DISCONNECT:
                 LOG.info("{} {} <{}>", direction, messageType, clientID);