There is a little difference between the output of domxml-to-native and the actual commandline.
No matter qemu is in control or readline mode, domxml-to-native always converts it to readline mode.

That is because the parameter "monitor_json" for qemuBuildCommandLine() is always set to false
in qemuDomainXMLToNative().
Signed-off-by: Ntangchen <tangchen@cn.fujitsu.com>