qmpclient: now if the QMP command starts with guest-+ , it will bind dynamicly to the VMID.qga socket

Signed-off-by: Wolfgang Link <wolfgang@linksystems.org>
shutdown by Qemu Guest Agent if the agent flag in the config is set

Important: "guest-shutdown" returns only by error a message.

Signed-off-by: Wolfgang Link <wolfgang@linksystems.org>
qmpclient: code cleanup, execute qga and qmp in parallel
simplify code by using vm_qmp_command() directly
qmpclient: improve error handling
qmpclient: fix mux_input regex