autotest/virt-test — pull request #1805 by will-Do (2014-08-25 09:17:37+00:00)
Title: libvirt_xml: update CPUXML and capabilityXML

Commit 393d19fa update class CPUXML without update related methods
of it, so fix it. And create a new func to do feature number check.

Signed-off-by: Yanbing Du