Port rebind should not be performed after soft accounting limit reached

A relay operator reports:

• their relay had accounting set
• it reached the soft limit and marked all connections for close
• when the period ended, it estimated that it would be active for the entire period
• then it attempted to rebind to ports, even though it had never closed the listeners

This appears to be a simple state management issue: https://lists.torproject.org/pipermail/tor-relays/2017-March/012151.html

I don't think the issue is restricted to OpenBSD.

I don't know if it's a regression, and I don't know if it should be fixed in 0.3.0. Given how annoying and confusing it is, we should probably backport it.