Issue #1983 Warn on connection failures

Signed-off-by: Greg Wilkins <gregw@webtide.com>

jetty-alpn/jetty-alpn-server/src/main/java/org/eclipse/jetty/alpn/server/ALPNServerConnectionFactory.java

@@ -104,6 +104,9 @@ public class ALPNServerConnectionFactory extends NegotiatingServerConnectionFact
                 return connection;
             }
         }
-        throw new IllegalStateException("No ALPNProcessor for " + engine);
+        
+        if (LOG.isDebugEnabled())
+            LOG.debug("No ALPNProcessor: {} {}",engine,endPoint);
+        throw new IllegalStateException("Connection rejected: No ALPN Processor for " + engine.getClass().getName() + " from " + processors);
     }
 }

jetty-io/src/main/java/org/eclipse/jetty/io/ManagedSelector.java

@@ -666,6 +666,7 @@ public class ManagedSelector extends ContainerLifeCycle implements Dumpable
         protected void failed(Throwable failure)
         {
             closeNoExceptions(channel);
+            LOG.warn(String.valueOf(failure));
             LOG.debug(failure);
         }
     }