Merge pull request #13802 from owncloud/share-partfilepermissions

Fix share permission checks

diff --cc apps/files_sharing/lib/sharedstorage.php
Simple merge

diff --cc apps/files_sharing/tests/sharedstorage.php
Simple merge

diff --cc apps/files_trashbin/lib/storage.php
Simple merge

diff --cc lib/private/connector/sabre/objecttree.php
Simple merge