Fix debugging for responses that Expire at check time (#1683)

Fix debugging for responses that Expire at check time (#1683)

Since 2000 commit 65fa5c6, our level-3 debugging mislead about Expires
being less than the check time when the two times were identical. The
actual checked conditions are correct: Roughly speaking, the response
with Expires value T is considered expired at that time T.

Also dropped extra (and inconsistent) trailing space on debugs() lines.
This space was added by the same 2000 commit, probably accidentally.