Gallery doesn't work in external storages which has previews disabled.

[SergioBertolinSG]

Steps to reproduce

1. Set up an external storage and disable previews.
2. Go to the folder and click on the gallery button.

Expected behaviour

We can show pictures.

Actual behaviour

Album is not available.

Server configuration

Operating system: Ubuntu 14.04

Web server: Apache

Database: MySQL

PHP version: 7.0

ownCloud version: (see ownCloud admin page) current master {"installed":"true","maintenance":"false","needsDbUpgrade":"false","version":"10.0.0.12","versionstring":"10.0.0","edition":"Enterprise","productname":"ownCloud"}

Updated from an older ownCloud or fresh install: Fresh

The content of config/config.php:

Are you using external storage, if yes which one: local/smb/sftp/... Yes, WND.

Are you using encryption: No

Logs

Client configuration

Browser Chrome, Safari.

Logs