lib/nsrep: fix a bug in choosing when many timed out

Commit 270d9964 was wrong (released in >= 2.4.0). I had reviewed that change carefully, but still I didn't notice the problem with continue just above the changed hunk.

This is yet another logically equivalent change after 270d9964. Now it's written in a way that expresses the original intention more clearly and without copy&paste or long lines.

It seems easiest to verify by inspecting the meaning of the code separartely for the two cases, based on condition: cur_addr_score < KR_NS_TIMEOUT