virsh_start: Need to ensure stopped before run

When run after virsh.shutdown, the first virsh.start was failing with
because the domain was already started.  Adjusted the .cfg file to
ensure setting of the 'kill_vm_before_test' in the status_error_no
variant.

Also, changed the error returned from using 'stdout' to 'stderr' so that
"Domain is already active" would be displayed.