Merge pull request #15489 from owncloud/dont_hide_exceptions_master

apps/user_ldap/lib/connection.php

apps/user_ldap/lib/user/manager.php

apps/user_ldap/tests/user_ldap.php

apps/user_ldap/user_ldap.php

core/js/share.js

core/templates/login.php

lib/base.php

lib/private/files/filesystem.php

lib/private/hook.php

lib/private/servernotavailableexception.php

lib/private/user/nouserexception.php

tests/lib/files/filesystem.php

tests/lib/preview.php