Fetch cluster slots from node upon first -MOVED response.

This is a more sane default as it allows users to indicate only a few
servers of the whole cluster composition, while it previously required
a more complex configuration of the client using client options.

This feature can be disabled using the "enableClusterNodes()" method.

lib/Predis/Connection/RedisCluster.php

@@ -46,7 +46,7 @@ use Predis\Command\RawCommand;
  */
 class RedisCluster implements ClusterConnectionInterface, IteratorAggregate, Countable
 {
-    private $askClusterNodes = false;
+    private $askClusterNodes = true;
     private $defaultParameters = array();
     private $pool = array();
     private $slots = array();

tests/Predis/Connection/RedisClusterTest.php

@@ -398,6 +398,7 @@ class RedisClusterTest extends PredisTestCase
         $connection2->expects($this->never())->method('writeCommand');
 
         $cluster = new RedisCluster();
+        $cluster->enableClusterNodes(false);
         $cluster->add($connection1);
         $cluster->add($connection2);
 
@@ -418,6 +419,7 @@ class RedisClusterTest extends PredisTestCase
         $connection2->expects($this->once())->method('readResponse')->with($command);
 
         $cluster = new RedisCluster();
+        $cluster->enableClusterNodes(false);
         $cluster->add($connection1);
         $cluster->add($connection2);
 
@@ -477,6 +479,7 @@ class RedisClusterTest extends PredisTestCase
         $factory->expects($this->never())->method('create');
 
         $cluster = new RedisCluster($factory);
+        $cluster->enableClusterNodes(false);
         $cluster->add($connection1);
         $cluster->add($connection2);
 
@@ -520,6 +523,7 @@ class RedisClusterTest extends PredisTestCase
                 ->will($this->returnValue($connection3));
 
         $cluster = new RedisCluster($factory);
+        $cluster->enableClusterNodes(false);
         $cluster->add($connection1);
         $cluster->add($connection2);
 
@@ -553,6 +557,7 @@ class RedisClusterTest extends PredisTestCase
         $factory->expects($this->never())->method('create');
 
         $cluster = new RedisCluster($factory);
+        $cluster->enableClusterNodes(false);
         $cluster->add($connection1);
         $cluster->add($connection2);
 
@@ -593,6 +598,7 @@ class RedisClusterTest extends PredisTestCase
                 ->will($this->returnValue($connection3));
 
         $cluster = new RedisCluster($factory);
+        $cluster->enableClusterNodes(false);
         $cluster->add($connection1);
         $cluster->add($connection2);