[libvirt] [test-API PATCH 0/5] Destroy class definition in utils.py

[Osier Yang]

These five patches are to change utils.py into a collection of functions.
And cleanup all of existing testcase to use the functions in it directly.

(1) Destroy Utils class definition
(2) Remove "util = utils.Utils()"
(3) Substitue "util." with "utils."
(4) Remove useless utils import "from utils import utils" in testcases where
    none of functions in utils.py is called

In testcase

from utils import utils
...
utils.functions(...)
...