Fixed bpop family does not return key value array when list is non-empty

[calvinlauyh]

Description:

When the list is non-empty, calling blpop and brpop calls the callback with only the value in the result

Affected methods:

• blpop
• brpop

Expected Behaviour:

The result in callback function should be [key, value]

Actual Behaviour:

The resultt in callback function contains only the value

Reference:

https://redis.io/commands/blpop#return-value