qemu: add vcpu.n.halted to vcpu domain stats
Extended qemuDomainGetStatsVcpu to include the per vcpu halted
indicator if reported by QEMU. The key for new boolean value
has the format "vcpu.<n>.halted".
Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com>
Reviewed-by: Bjoern Walk <bwalk@linux.vnet.ibm.com>