autotest/virt-test — pull request #1563 by Hao-Liu (2014-04-01 19:11:32+00:00)
Title: virttest.libvirt_xml: Add class for cputune entry

1) Use a dedicated class VMCPUTune to manipulate `` tag
instead of using a tag string and a lot of attributes which is
not intuitive when using.

2) Add a simple getter setter delter unittest for this class.

3) Fixed two ` is not ` to ` != `.
The first one is identity test and will not alway get `False`
even if two strings are equal.

Signed-off-by: Hao Liu