[libvirt] Qemu Commandline options are ignored during migration

Heyho Guys, The domain defintion xml allows to extend the qemu command. For example: ``` <qemu:commandline> <qemu:arg value='-cpu'/> <qemu:arg value='SandyBridge,-kvm_steal_time'/> </qemu:commandline> ``` The options are correctly passed on startup, but the migration will ignore them. The desination xml is dumped with the flags 1|2|8. (secure, inactive and migrateable) `secure` flag is required to keep vnc passwords, and inactive to keep the metadata section. But i also mentioned that qemu:commandline section needs inactive flag too. -- Tim Foerster