gcs: Check for errors when testing bucket is OK in mkdir #1590

Previously we would check the bucket's status and on error we would
try to create it.  Now we only try to create it if we got a not found
error, otherwise we report the error to the user.

googlecloudstorage/googlecloudstorage.go

@@ -578,6 +578,12 @@ func (f *Fs) Mkdir(dir string) error {
 		// Bucket already exists
 		f.bucketOK = true
 		return nil
+	} else if gErr, ok := err.(*googleapi.Error); ok {
+		if gErr.Code != http.StatusNotFound {
+			return errors.Wrap(err, "failed to get bucket")
+		}
+	} else {
+		return errors.Wrap(err, "failed to get bucket")
 	}
 
 	if f.projectNumber == "" {