qemuProcessSetupPid: Use @numatune variable more

qemuProcessSetupPid: Use @numatune variable more

Inside of qemuProcessSetupPid() there's @numatune variable which
is set to vm->def->numa, but it lives only in one block. In the
rest of places the expanded form (vm->def->numa) is used instead.
Move the variable declaration at the beginning of the function
and use it instead of the expanded form.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Martin Kletzander <mkletzan@redhat.com>