Most code now uses the virProcess / virCommand APIs, so
the need for sys/wait.h is quite limited. Removing this
include removes the dependency on GNULIB providing a
dummy sys/wait.h for Windows.
Reviewed-by: NPavel Hrdina <phrdina@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>