spec: require libvirt 0.10.2-29.el6_5.4

A libvirt race condition caused the volume watermark to be reported as
large as the physical size triggering an extension at the end of each
live migration.

This patch adds the requirement for the new libvirt package in order to
fix the issue.

Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1038069
Change-Id: I2f57c3f4ee2f5b3d27a1ddbe2faa976120f3da42
Signed-off-by: Federico Simoncelli <fsimonce@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/24392
Reviewed-by: Dan Kenigsberg <danken@redhat.com>