libvirt.test: Add 2 more options test for undefine

Add '--wipe-storage' and '--remove-all-storage' option
test for virsh undefine.

Signed-off-by: Li Yang <liyang.fnst@cn.fujitsu.com>
Merge pull request #141 from liyangfnst/undefine_opt

libvirt.test: Add 2 more options test for undefine