[#411] Don't check object tags on deletion

By specification https://docs.aws.amazon.com/AmazonS3/latest/userguide/tagging-and-policies.html
we shouldn't check object tags on PUT and DELETE

Signed-off-by: Denis Kirillov <d.kirillov@yadro.com>

api/middleware/policy.go

@@ -32,7 +32,9 @@ const (
 	amzTagging     = "x-amz-tagging"
 )
 
-// At the beginning of these operations resources haven't yet been created.
+// In these operations we don't check resource tags because
+// * they haven't been created yet
+// * resource tags shouldn't be checked by AWS spec.
 var withoutResourceOps = []string{
 	CreateBucketOperation,
 	CreateMultipartUploadOperation,
@@ -43,6 +45,8 @@ var withoutResourceOps = []string{
 	ListPartsOperation,
 	PutObjectOperation,
 	CopyObjectOperation,
+	DeleteObjectOperation,
+	DeleteMultipleObjectsOperation,
 }
 
 type PolicySettings interface {