Cache_redis, delete() method: Bringing back a line of code.
diff --git a/system/libraries/Cache/drivers/Cache_redis.php b/system/libraries/Cache/drivers/Cache_redis.php
index 21ef991..2037878 100644
--- a/system/libraries/Cache/drivers/Cache_redis.php
+++ b/system/libraries/Cache/drivers/Cache_redis.php
@@ -134,6 +134,9 @@
 	 */
 	public function delete($key)
 	{
+		// This is for not leaving garbage keys within the Redis auxilary set.
+		$this->_redis->sRemove('_ci_redis_serialized', $key);
+
 		return ($this->_redis->delete($key) === 1);
 	}