Revert requiring a recent positive check result

Revert "Enable zuul gerrit debug logging"

This reverts commit def03556bc36169e39c909471b0fedd5f5acfec2.

Revert "narrow the freshness window to 24h"

This reverts commit 20f5d2d0034641bc96e822c6846d3b5886dbe119.

Revert "Require a recent (48h) positive check result"

This reverts commit a78022f9d4bce9296b600dfb8992c1d4e063852e.

There is a bug that is causing the automatic gate enqueue after
a verify+1 to fail.  Revert this until we track it down.

Change-Id: I7347e2e999855e79177ec5f670392334c92d628d