JedisSentinelPool now takes care of multi failover

* Now Pool.initPool() call closeInternalPool(), instead of destroy()
** calling destroy() in Pool.initPool() may have side effect, and JedisSentinelPool did
* modify unit test to test failover twice (needs +1 slave)
** modify configurations for additional slave

pom.xml

@@ -45,7 +45,7 @@
   </scm>
 
 	<properties>
-		<redis-hosts>localhost:6379,localhost:6380,localhost:6381,localhost:6382</redis-hosts>
+		<redis-hosts>localhost:6379,localhost:6380,localhost:6381,localhost:6382,localhost:6383</redis-hosts>
 		<sentinel-hosts>localhost:26379,localhost:26380</sentinel-hosts>
     <github.global.server>github</github.global.server>
 	</properties>