autotest/autotest — pull request #196 by ypu (2012-02-24 08:16:19+00:00)
Title: Virt tests: Move image_func outside the loop of vms

Update process put image_func outside the loop of vms to make the
image_func can work for cases don't need to boot up vm. Such as some
tests related with qcow2.

And fix the missing docstring for vm_first.

Signed-off-by: Yiqiao Pu