ui: fix store never removed from /stores page bug

We need to update `LastCheck` only if the error is non-nil. That field
is used in the cleanup function to know when to remove the StoreAPI from
the UI. If we always update it, even if an error has happened, that
means that `--store.unhealthy-timeout` is never respected.

Signed-off-by: Giedrius Statkevičius <giedriuswork@gmail.com>

CHANGELOG.md

@@ -17,6 +17,7 @@ We use *breaking* word for marking changes that are not backward compatible (rel
 - [#2231](https://github.com/thanos-io/thanos/pull/2231) Bucket Web - Sort chunks by thanos.downsample.resolution for better grouping
 - [#2254](https://github.com/thanos-io/thanos/pull/2254) Bucket: Fix metrics registered multiple times in bucket replicate
 - [#2271](https://github.com/thanos-io/thanos/pull/2271) Bucket Web: Fixed Issue #2260 bucket passes null when storage is empty
+- [#2339](https://github.com/thanos-io/thanos/pull/2339) Query: fix a bug where `--store.unhealthy-timeout` was never respected
 
 ### Added
 

pkg/query/storeset.go

@@ -457,10 +457,9 @@ func (s *StoreSet) updateStoreStatus(store *storeRef, err error) {
 	}
 
 	status.LastError = err
-	status.LastCheck = time.Now()
 
 	if err == nil {
-
+		status.LastCheck = time.Now()
 		mint, maxt := store.TimeRange()
 		status.LabelSets = store.LabelSets()
 		status.StoreType = store.StoreType()