merge jetty-9.2.x into jetty-9.3.x

VERSION.txt

@@ -47,6 +47,13 @@ jetty-9.3.15.v20161220 - 20 December 2016
  + 1186 Where can i find SocketConnector .java and
    BlockingChannelConnector.java etc?
 
+jetty-9.2.21.v20170120 - 20 January 2017
+ + 592 Support no-value Host header in HttpParser
+ + 1229 ClassLoader constraint issue when using NativeWebSocketConfiguration
+   with WEB-INF/lib/jetty-http.jar present
+ + 1267 Request.getRemoteUser can throw undeclared IllegalStateException via
+   DeferredAuthentication & FormAuthenticator
+
 jetty-9.3.14.v20161028 - 28 October 2016
  + 292 NPE in SslConnectionFactory newConnection
  + 295 Ensure Jetty Client use of Deflater / Inflater calls .end() to avoid