CLOUDSTACK-9348: Make NioConnection selector blocking by timeout

Uses timeout based selector blocking. This makes connection handling
aggressive safely.

Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>

Author: yadvr

utils/src/com/cloud/utils/nio/NioConnection.java

@@ -130,7 +130,7 @@ public void run() {
 
         while (_isRunning) {
             try {
-                _selector.select();
+                _selector.select(1000);
 
                 // Someone is ready for I/O, get the ready keys
                 Set<SelectionKey> readyKeys = _selector.selectedKeys();