Fix to not destroy draggable when no draggable was set

When a dir has no delete permission, the draggable isn't initialized on
files. This fix makes sure we don't try to destroy a draggable when it
wasn't inited in the first place.

Fixes #6254
Merge pull request #6264 from owncloud/files-draggabledestroy

Fix to not destroy draggable when no draggable was set
updated description of the files encryption app
webdav: return SPACE_UNKNOWN if server do not support quota

Signed-off-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Fix array access syntax for older PHP

There was a syntax error when running tests in PHP 5.3.10.
Merge pull request #6807 from owncloud/enc_updated_description

updated description of the files encryption app
Merge pull request #6810 from kofemann/for-upstream

webdav: return SPACE_UNKNOWN if server do not support quota
Merge pull request #6812 from owncloud/tests-fixcachesyntaxforoldphp

Fix array access syntax for older PHP
add link to documentation
show link to app documentation
Merge branch 'add_documentation_to_appinfo' of github.com:owncloud/core into add_documentation_to_appinfo