support for expected_failure explicit message
support for expected_failure explicit message

shuhaowu/gh-ost,druud62/gh-ost,wfxiang08/gh-ost,shuhaowu/gh-ost,druud62/gh-ost,groenewold-pythian/gh-ost,wfxiang08/gh-ost,groenewold-pythian/gh-ost