Now, that our virCommandSetPidFile() is more intelligent we don't
need to rely on the daemon to create and lock the pidfile and use
virCommandSetPidFile() at the same time.

NOTE that as advertised in the previous commit, this was
temporarily broken, because both virCommand and
qemuProcessStartManagedPRDaemon() would try to lock the pidfile.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NMarc-André Lureau <marcandre.lureau@redhat.com>