KVM-test: Log the output of failed executed command 'pre/post-command'

Sometimes we need the output of failed command 'pre/post-command'
when raising error.TestError. Take an example that using post-command
to check images of qcow2 format, it will simply tell command failed
rather than show '%d errors were found on the image'.

Signed-off-by: Yolkfull Chow <yzhou@redhat.com>


git-svn-id: http://test.kernel.org/svn/autotest/trunk@4185 592f7852-d20e-0410-864c-8624ca9c26a4
1 file changed