addrmgr: Properly scale up.

Commit c80c8e7
was supposed to mimic
Bitcoin Core commit 1d21ba2f5ecbf03086d0b65c4c4c80a39a94c2ee
in order to implement the suggested Countermeasure 6 in
Eclipse Attacks on Bitcoin’s Peer-to-Peer Network, Ethan
Heilman, Alison Kendler, Aviv Zohar, Sharon Goldberg. ePrint Archive
Report 2015/263. March 2015.

However, erroneously the triedBucketSize was increased instead of the
triedBucketCount.

This commit fixes this error in order to properly mimic the Bitcoin Core
commit referenced above.

This change in isolation is problematic, because after applying it old
peers.json files will still load, but with many empty new tried buckets and
potentially overfull old tried buckets.

See issue decred#1131 for discussion.

addrmgr/addrmanager.go

@@ -107,11 +107,11 @@ const (
 
 	// triedBucketSize is the maximum number of addresses in each
 	// tried address bucket.
-	triedBucketSize = 256
+	triedBucketSize = 64
 
 	// triedBucketCount is the number of buckets we split tried
 	// addresses over.
-	triedBucketCount = 64
+	triedBucketCount = 256
 
 	// newBucketSize is the maximum number of addresses in each new address
 	// bucket.