Dont set node status as down

Just print out trace messages when retrieving mc stats and exceptions
launch. It may mask out the real reason when simply mark node
status as down.

collector.py

@@ -211,7 +211,7 @@ def get_mc_stats(self, server, bucketlist, nodes, bucketname):
                             self.get_mc_stats_per_node(mc, stats)
                             stats_buffer.node_stats[bucket_name][node['hostname']] = stats
                         except Exception, err:
-                            stats_buffer.nodes[node['hostname']]['status'] = 'down'
+                            #stats_buffer.nodes[node['hostname']]['status'] = 'down'
                             traceback.print_exc()
 
     def get_ns_stats(self, bucketlist, server, port, user, password, bucketname, scale, opts):