loads not virtualized in sysinfo()

`loads` field in `sysinfo()` always returns the host's load average. `sysinfo()` is used e.g. by `uptime` in busybox.

```
ct new --distribution alpine testct
ct netif new bridge --link lxcbr0 testct eth0
ct start testct
sleep 15
ct exec testct apk add strace
ct exec testct strace -e sysinfo uptime
```