Target JDK7, use getHostString instead of getHostName, close AsyncHttpClient#672

Author: Stephane Landelle

providers/netty/src/main/java/org/asynchttpclient/providers/netty/channel/SslInitializer.java

@@ -41,7 +41,7 @@ public void connect(ChannelHandlerContext ctx, SocketAddress remoteAddress, Sock
             throws Exception {
 
         InetSocketAddress remoteInetSocketAddress = (InetSocketAddress) remoteAddress;
-        String peerHost = remoteInetSocketAddress.getHostName();
+        String peerHost = remoteInetSocketAddress.getHostString();
         int peerPort = remoteInetSocketAddress.getPort();
 
         SslHandler sslHandler = channelManager.createSslHandler(peerHost, peerPort);