Upgrade Netty 3.6.6.Final, close AsyncHttpClient#306

Author: Stephane Landelle

providers/netty/pom.xml

@@ -17,7 +17,7 @@
         <dependency>
             <groupId>io.netty</groupId>
             <artifactId>netty</artifactId>
-            <version>3.6.5.Final</version>
+            <version>3.6.6.Final</version>
         </dependency>
     </dependencies>