add libvirt min version check

[Dan Prince]

We should add a check to Nova compute so that on startup it checks the min required libvirt version. This would potentially head of some rather cryptic compute bugs that can occur if you try to use an older libvirt version with Nova.

I recently hit some issues with the virDomain.reset() call being used to reboot instances in Nova.

The min required version for resize seems to be 0.9.7... see following command from danpb:

# eu-readelf -a /usr/lib64/libvirt.so | grep virDomainReset | grep LIBVIRT
  599: 00000000000dc3f0 551 FUNC GLOBAL DEFAULT 12 virDomainReset@@LIBVIRT_0.9.7

So it appears 0.9.7 is now our new min required version.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/8474

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/8474
Committed: http://github.com/openstack/nova/commit/f28731c1941e57b776b519783b0337e52e1484ab
Submitter: Jenkins
Branch: master

commit f28731c1941e57b776b519783b0337e52e1484ab
Author: Dan Prince <email address hidden>
Date: Wed Jun 13 10:11:04 2012 -0400

    Add libvirt min version check.

    Fixes LP Bug #1012689.

    Change-Id: I91c0b7c41804b2b25026cbe672b9210c305dc29b