Fix SELECT command in Pipeline (#3301)

Author: sazzad16

src/main/java/redis/clients/jedis/Pipeline.java

@@ -4272,7 +4272,7 @@ public Response<List<String>> time() {
 
   @Override
   public Response<String> select(final int index) {
-    return appendCommand(new CommandObject<>(commandObjects.commandArguments(Protocol.Command.SELECT), BuilderFactory.STRING));
+    return appendCommand(new CommandObject<>(commandObjects.commandArguments(Protocol.Command.SELECT).add(index), BuilderFactory.STRING));
   }
 
   @Override

src/test/java/redis/clients/jedis/PipeliningTest.java

@@ -157,9 +157,13 @@ private void verifyHasBothValues(byte[] firstKey, byte[] secondKey, byte[] value
 
   @Test
   public void pipelineSelect() {
+    jedis.set("foo", "bar");
+    jedis.swapDB(0, 1);
     Pipeline p = jedis.pipelined();
+    p.get("foo");
     p.select(1);
-    p.sync();
+    p.get("foo");
+    assertEquals(Arrays.<Object>asList(null, "OK", "bar"), p.syncAndReturnAll());
   }
 
   @Test