[#1634] node: Do not return expired objects

If an object has not been marked for removal by the GC in the current epoch
yet but has already expired, respond with `ErrObjectNotFound` api status.
Also, optimize shard iteration: a node must stop any iteration if the object
 is found but gonna be removed soon.
All the checks are performed by the Metabase.

Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>

pkg/local_object_storage/engine/put.go

@@ -76,6 +76,12 @@ func (e *StorageEngine) put(prm PutPrm) (PutRes, error) {
 
 			exists, err := sh.Exists(existPrm)
 			if err != nil {
+				if shard.IsErrObjectExpired(err) {
+					// object is already found but
+					// expired => do nothing with it
+					finished = true
+				}
+
 				return // this is not ErrAlreadyRemoved error so we can go to the next shard
 			}