Add virsh testcase virsh_blockresize

  domain/virsh_blockresize.py
  domain/virsh_blockresize.cfg

Signed-off-by: Guannan Ren <gren@redhat.com>
Fix pep8 problems of virsh blockresize test.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
Merge pull request #127 from yumingfei/blockresize

Rebase: Add virsh testcase virsh_blockresize