remove reset after connection was returned to pool (#1935)

Fix #1920 (#1918)
Fix bad backport of commit

Author: gkorland

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

@@ -3636,7 +3636,6 @@ public void close() {
       } else {
         pool.returnResource(this);
       }
-      this.dataSource = null;
     } else {
       super.close();
     }