Update indexer.php

Reduce the verbosity in the owncloud.log (and save a little bit of time) by skipping the extractMetadata() logic when dealing with directories
use link_to_docs function to hook up proper links for oc6
Fixed slideshow to not register file action outside of files app

Fixes #1474 where the slideshow opened itself from the trash bin.
Merge pull request #1475 from owncloud/slideshow-notrash

Fixed slideshow to not register file action outside of files app
Merge pull request #1463 from owncloud/fixing-doc-links-firstrun

use link_to_docs function to hook up proper links for oc6
Merge pull request #1284 from gwolf/patch-1

Update indexer.php
Slideshow is now disabled by default from the gallery app

When opening the slideshow from the gallery app it is now also disabled
by default.
Merge pull request #1477 from owncloud/gallery-slideshowstoppedbydefault

Slideshow is now disabled by default from the gallery app
Merge branch 'master' into fix-gallery-sharing-oc6
fixing 'Uncaught TypeError: Cannot read property 'length' of undefined'