Images set as hidden files should not be shown in Gallery app when 'show hidden files option' is not active

[davitol]

Steps to reproduce

1. Upload an image
2. Rename it with a dot at the beginning (it turns into a hidden file)
3. Go to Gallery section

Expected behaviour

The images files set as hidden should not be shown in the gallery

Actual behaviour

The images are shown in the gallery

Server configuration

Operating system:
Ubuntu 16.04
Web server:
PHP dev server
Database:
mySQL
PHP version:
7.1
ownCloud
cloud version:
core stable10 at 10.0.9RC3 and Gallery app branch release/16.1.0