libvirt.test: Fix qemu-ga service bug for reboot and shutdown test

Signed-off-by: Li Yang <liyang.fnst@cn.fujitsu.com>
libvirt.test: Skip option unsupported test only in positive test

Signed-off-by: Li Yang <liyang.fnst@cn.fujitsu.com>
libvirt.test: Skip test if option isn't supported

Signed-off-by: Li Yang <liyang.fnst@cn.fujitsu.com>
svirt: rewrite test for svirt_install.

As this test only care whether the qemu-kvm process
can access the image. It is not necessary to install
a full os in a vm. Just verify the vm is alive after
virt-install command is enough. Then we can save a lot
of time and make this test independent from unattended_install.

Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Merge pull request #255 from yangdongsheng/svirt

svirt_install:  simplify svirt_install test.
libguestfs.test: Fix a bug in virt-sysprep test

Signed-off-by: Li Yang <liyang.fnst@cn.fujitsu.com>
Merge pull request #258 from liyangfnst/attach_device_skip

libvirt.test: Skip test if option isn't supported
Merge pull request #257 from liyangfnst/dumpxml_opt_fix

libvirt.test: Skip option unsupported test only in positive test
Merge pull request #256 from liyangfnst/reboot_shutdown_agent

libvirt.test: Fix qemu-ga service bug for reboot and shutdown test
Merge pull request #263 from liyangfnst/sysprep_fix

libguestfs.test: Fix a bug in virt-sysprep test
libvirt.tests: Add tests for vcpu plug/unplug with different scenarios

Signed-off-by: Yanbing Du <ydu@redhat.com>