qemu: Translate features in virQEMUCapsGetCPUFeatures
Starting with QEMU 4.1 qemuMonitorCPUModelInfo structure in virQEMUCaps stores only canonical feature names which may differ from the name used by libvirt. We need translate these canonical names into libvirt names for further consumption.
This fixes a bug in qemuConnectBaselineHypervisorCPU which would remove all features for which libvirt's spelling differs from the QEMU's preferred name. For example, the following result of qemuConnectBaselineHypervisorCPU on my host with QEMU 4.1 is wrong: