BUG/MINOR: peers: make sure to always apply offsets to now_ms in expiration

BUG/MINOR: peers: make sure to always apply offsets to now_ms in expiration

Now_ms can be zero nowadays, so it's not suitable for direct assignment to
t->expire, as there's a risk that the timer never wakes up once assigned
(TICK_ETERNITY). Let's use tick_add(now_ms, 0) for an immediate wakeup
instead. The impact here might be a reconnect programmed upon signal
receipt at the wrapping date not having a working timeout.

This should be backported where it applies.