qemu: Implement new QMP command for cpu hotplug
qemu: Implement new QMP command for cpu hotplug

This patch implements support for the "cpu-add" QMP command that plugs
CPUs into a live guest. The "cpu-add" command was introduced in QEMU
1.5. For the hotplug to work machine type "pc-i440fx-1.5" is required.

jfehlig/libvirt,shugaoye/libvirt,jfehlig/libvirt,fabianfreyer/libvirt,elmarco/libvirt,libvirt/libvirt,eskultety/libvirt,andreabolognani/libvirt,nertpinx/libvirt,andreabolognani/libvirt,shugaoye/libvirt,cbosdo/libvirt,datto/libvirt,eskultety/libvirt,zippy2/libvirt,zippy2/libvirt,zhlcindy/libvirt-1.1.4-maintain,zhlcindy/libvirt-1.1.4-maintain,jardasgit/libvirt,andreabolognani/libvirt,zippy2/libvirt,rlaager/libvirt,agx/libvirt,nertpinx/libvirt,datto/libvirt,olafhering/libvirt,olafhering/libvirt,elmarco/libvirt,taget/libvirt,crobinso/libvirt,VenkatDatta/libvirt,cbosdo/libvirt,fabianfreyer/libvirt,cbosdo/libvirt,taget/libvirt,libvirt/libvirt,agx/libvirt,andreabolognani/libvirt,rlaager/libvirt,jardasgit/libvirt,crobinso/libvirt,VenkatDatta/libvirt,agx/libvirt,datto/libvirt,VenkatDatta/libvirt,libvirt/libvirt,jardasgit/libvirt,olafhering/libvirt,elmarco/libvirt,rlaager/libvirt,jardasgit/libvirt,VenkatDatta/libvirt,zippy2/libvirt,shugaoye/libvirt,elmarco/libvirt,taget/libvirt,jfehlig/libvirt,shugaoye/libvirt,VenkatDatta/libvirt,agx/libvirt,nertpinx/libvirt,andreabolognani/libvirt,shugaoye/libvirt,eskultety/libvirt,olafhering/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,zhlcindy/libvirt-1.1.4-maintain,agx/libvirt,cbosdo/libvirt,nertpinx/libvirt,zhlcindy/libvirt-1.1.4-maintain,crobinso/libvirt,eskultety/libvirt,crobinso/libvirt,fabianfreyer/libvirt,taget/libvirt,datto/libvirt,rlaager/libvirt,zhlcindy/libvirt-1.1.4-maintain,fabianfreyer/libvirt,eskultety/libvirt,elmarco/libvirt,libvirt/libvirt,datto/libvirt,jfehlig/libvirt,nertpinx/libvirt,taget/libvirt,cbosdo/libvirt,rlaager/libvirt