qemu: Fix race condition when detaching a device

qemu: Fix race condition when detaching a device

If QEMU replies to device_del command with "DeviceNotFound"
error, then libvirt doesn't clean the device from the live
configuration.

This is because qemuMonitorDelDevice() returns -2 to
qemuDomainDeleteDevice() and instead of calling
qemuDomainRemoveDevice() the qemuDomainDetachDeviceLive() jumps
right onto cleanup label.

Resolves: https://gitlab.com/libvirt/libvirt/-/issues/359
Signed-off-by: Pierre LIBEAU <pierre.libeau@corp.ovh.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>