libvirt: Introduce console_verify

Move the function from the test virsh_console.

Signed-off-by: Kyla Zhang <weizhan@redhat.com>
virttest.virsh: Add interface for virsh create

So that virsh create tests can be implemented.

Signed-off-by: Kyla Zhang <weizhan@redhat.com>
Merge pull request #1420 from autotest/virsh-create

Virsh create - PR 1353 remake