Description of problem:
libvirt restore guest fail  with low probability and report qemu-kvm smbios error.
virsh restore $guest fail. but if you try again , it will be successed .

libvirt-0.9.8-1.el6.x86_64 can not reproduce this bug  so it is a regression 

Version-Release number of selected component (if applicable):
libvirt-0.9.9-2.el6.x86_64
qemu-kvm-0.12.1.2-2.222.el6.x86_64


How reproducible:
about 5%

Steps to Reproduce:
1. define a guest with xml like (RHEV's guest has smbios setting ) :
...
<sysinfo type='smbios'>
<system>
<entry name='manufacturer'>Red Hat</entry>
<entry name='product'>RHEV Hypervisor</entry>
<entry name='version'>6Server-6.2.0.3.el6</entry>
<entry name='serial'>44454C4C-4A00-1047-804A-C2C04F4D3258_00:23:19:2D:52:90</entry>
<entry name='uuid'>b075feff-dfb5-6b29-3734-e0aa0d8ed56a</entry>
</system>
</sysinfo>
<os>
<type arch='x86_64' machine='rhel6.2.0'>hvm</type>
<boot dev='hd'/>
<boot dev='network'/>
<bootmenu enable='yes'/>
<smbios mode='sysinfo'/>
</os>
...


2.  create  this guest
# virsh create ruth.xml
3.  let guest  save and restore  in the loop

#while true ;do virsh save rr62 /tmp/save && virsh restore /tmp/save ;done


note: when virsh restore fail  error is :
error: Failed to restore domain from /tmp/save
error: unsupported configuration: the QEMU binary /usr/libexec/qemu-kvm does not support smbios settings

4.in the same time  watch the libvirt log   , then restore fail  the error show up

#tail -f  /var/log/libvirt/libvirtd.log
...
2012-02-08 05:55:46.241+0000: 29371: error : qemuBuildCommandLine:3681 : unsupported configuration: the QEMU binary /usr/libexec/qemu-kvm does not support kvm
2012-02-08 05:55:46.241+0000: 29371: error : qemuBuildCommandLine:3815 : unsupported configuration: the QEMU binary /usr/libexec/qemu-kvm does not support smbios settings
....



RUTH test can reproduce this issue 100%


#ruth -ld -vvv ../config/vmTests-new.conf -f vmTests.HibernateVmTests.repeatedHibernationCycle

result is fail    the log is the same with  pure libvirt .




Actual results:
virsh restore fail

Expected results:
no fail

Additional info:
this issue is hard to reproduce with pure libvirt ,but it can reproduce easily with RUTH