Fixed deviceCount,onlineCount,activeCount平台是小写开头

[pengesoft]

You need to complete

• [x] unit tests and/or feature tests
• [x] documentation is changed or added

[CLAassistant]

Thank you for your submission, we really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[AxiosLeo]

@pengesoft 我看了 Iot 产品方的接口定义，确实是小写的。

SDK 是由生成器根据 产品方 定义的 接口 生成的，所以不能手动修改。