The simplejson library has been generally used in OpenStack in the past
to implement compatibility with Python 2 and Python 3. However now
python 2 is no longer supported, and we can use the built-in json
module.
Note that the built-in json module does not accept byte values, while
these were automatically decoded by simplejson using utf-8 encoding.
Add encoding option to all subprocess calls so that outputs are all
encoded strings and can be passed directly into json data.
Change-Id: Ibfd47e87994511198d8883a91978be542dac3a3e
42bfac519b