For compatibility with more relaxed transfer providers.

This prevents creating journal if it didn't exist before and we
only want to read from it. Journal sync and reload caused this.

places.

new_serial should be initialized

refs #181

close #181

This actually solves only half of the problem, reverting for now.

This reverts commit 8caf9941.

This is a backport from packet-api-rewrite branch (sort of).
The problem is when we add a socket to the set and then do a lengthy
operation (transfer answer), it may be sweeped at the end without a
chance of querying.