block_hotplug:
1.replace hotplug device definations by qcontainer.images_define_
by_params()
2.remove useless options in block_hotplug.cfg
3.replace hotplug/verify_hot|unplug by simple_hot|unplug()
4.extract sub_tests to run_sub_test()
Signed-off-by: NAihua Liang <aliang@redhat.com>