**Expected behavior**: Disabling DNS seeding (`-dnsseed=0`) should make Bitcoin Core use the fixed seed nodes immediately on startup (assuming an empty `peers.dat`).

**Actual behavior**:  The fixed seed nodes are used but only after an unnecessary 60 second timeout, and a somewhat misleading log message ("Adding fixed seed nodes as DNS doesn't seem to be available.").

**To reproduce**: `rm ~/.bitcoin/peers.dat && src/bitcoind -dnsseed=0` and wait... 💤 

This issue is probably a "good first issue" :)
{
    if (net == NET_UNROUTABLE || net == NET_INTERNAL)
        return;
    LOCK(cs_mapLocalHost);
    vfLimited[net] = !reachable;
}
bool IsReachable(enum Network net)