This commit modifies the recently modified logic for self-channel
retransmission to exclude pruning *our* channels which haven’t been
updated since the broadcastInterval. Instead, we only re-broadcast
channels of ours that haven’t been updated in 24 hours.
This commit fixes an existing bug in the announcement processing of the
authenticated gossiper. We will now only examine an incoming
announcement for validity if it targets the chain that we’re currently
active on.
