xend: Fix scheduler parameters of rebooted domain

xend: Fix scheduler parameters of rebooted domain

When I changed the scheduler parameters of a domain with
xm sched-credit, the information of xm sched-credit was changed.
But as for the information of xm list, the values of the domain
configuration definition were kept.
And, then I rebooted the domain. The information of xm list was
not changed. But as for the information of xm sched-credit, the
values of the domain configuration definition were returned.

# xm create /xen/PVdomain.1 cpu_cap=150 cpu_weight=512
Using config file "/xen/PVdomain.1".
Started domain PVdomain.1
# xm sched-credit -d PVdomain.1
Name                              ID Weight Cap
PVdomain.1                         1    512  150
# xm sched-credit -d PVdomain.1 -c 75 -w 384
# xm sched-credit -d PVdomain.1
Name                              ID Weight Cap
PVdomain.1                         1    384   75
# xm list --long PVdomain.1 | grep cpu_
    (cpu_weight 512)
    (cpu_cap 150)
    (cpu_time 29.353831745)
# xm reboot PVdomain.1
# xm sched-credit -d PVdomain.1
Name                              ID Weight Cap
PVdomain.1                         2    512  150
# xm list --long PVdomain.1 | grep cpu_
    (cpu_weight 512)
    (cpu_cap 150)
    (cpu_time 5.950247186)

If the scheduler parameters of the domain were changed with
xm sched-credit, I think that xm list should show the current
values about the scheduler parameters.
And, then if the domain is rebooted, I think that the rebooted
domain should keep the preceding values about the scheduler
parameters.

Signed-off-by: Masaki Kanno <kanno.masaki@jp.fujitsu.com>