virttest.env_process: Remove restart_vm option

The restart_vm option, that will restart a vm at the beginning
of postprocessing, is unnecessary, given that you could
simply shut down all the VMs at the end of each test,
forcing new vms to be started.

So get rid of this option, and replace --restart-vm
in ./run to use kill_vm = yes instead.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
Merge pull request #1214 from autotest/restart-vm

virttest.env_process: Remove restart_vm option
virsh_setvcpus: Update test

Update the config/test to follow more "modern" practices, especially
with respect to _domain vs. _vm_ref variables in cfg file. Found instances
where _vm_ref was being used instead of _options - fixed that too.

Adjust test flow to use try/finally for the test conditions. Rather than
relying on /etc/libvirt/qemu/%s.xml for running/defined domain output,
use the dumpxml() function with and without --inactive based on whether
the test is adjusting the "--config" or otherwise.  Adjust the usage of
temporary xml files to use the tmp directory.  Use the more commonly
used new_from_inactive_dumpxml() to save/restore the original configuration.
Finally rather than relying on the generated xml format to re.search
to find the current value, grab that from the XML.  The issue with the
current code is that a new property "placement=<string>" was added and
the result was the re.search would never succeed the way it was written.

Use TestNAError for remote tests when not configured properly and also
for the qemu 1.5 error string check since hotplug is not supported until
that release.
merge-eventually