Go to the Huawei site and request a bootloader unlock code. While you're there download the stock firmware. You don't necessarily have to wait for the bootloader unlock code there is a tool that will give you the code.
Unlock the bootloader in fastboot, reboot. Go back to fastboot. Using the power key and volume keys. Don't use adb reboot bootloader! Then flash the Twrp recovery and SuperSU. Reboot it may boot normally and may not it may just boot right back into Twrp. If it does then power off and go back to fastboot mode.
Open the update file in the Huawei firmware for you device using Huawei update extractor. Copy and paste the stock recovery.img in your working folder. Fastboot flash the stock recovery and reboot. You will have a rooted device.