Merge release branch 4.8 to master

* 4.8:
  Additional exception logging for Cloudstack-9285

Author: swill

agent/src/com/cloud/agent/Agent.java

@@ -227,6 +227,7 @@ public void start() {
         try {
             _connection.start();
         } catch (final NioConnectionException e) {
+            s_logger.warn("NIO Connection Exception  " + e);
             s_logger.info("Attempted to connect to the server, but received an unexpected exception, trying again...");
         }
         while (!_connection.isStartup()) {
@@ -235,6 +236,7 @@ public void start() {
             try {
                 _connection.start();
             } catch (final NioConnectionException e) {
+                s_logger.warn("NIO Connection Exception  " + e);
                 s_logger.info("Attempted to connect to the server, but received an unexpected exception, trying again...");
             }
         }
@@ -412,6 +414,7 @@ protected void reconnect(final Link link) {
             try {
                 _connection.start();
             } catch (final NioConnectionException e) {
+                s_logger.warn("NIO Connection Exception  " + e);
                 s_logger.info("Attempted to connect to the server, but received an unexpected exception, trying again...");
             }
             _shell.getBackoffAlgorithm().waitBeforeRetry();