use and cache root storage info if a share can't be resolved
use and cache root storage info if a share can't be resolved

as is a broken share will never be cached

Signed-off-by: Robin Appelman <474ee9ee179b0ecf0bc27408079a0b15eda4c99d@icewind.nl>

nextcloud/server,nextcloud/server,nextcloud/server,nextcloud/server