stablerangecache: fix output in the drifted case The node were not hex, and the field had different order in the pair. This is now fixed.

sqlcache: also ignore integrity error integrity error can happens when multiple client tries to warm similar cache. Given we leave multiple hole in the cache that can be warmed by anyone, this is harder to avoid that we would like. We simply catch the error in this case. Someone will warm the missing entry later.

sqlcache: cache OperationError when saving This is a cache, so we should not crash when trying to operate on it. OperationError can happens when the database is seen as readonly or locked.