Make SMB module more fault-tolerant
Make SMB module more fault-tolerant

Ignore unavailable files when fetching the share's mtime
or reading directory listings. This can happen on servers using a
distributed file system (DFS) with unavailable destinations, for example
when the remote server is offline.

Signed-off-by: Roland Tapken <0d270388f2f92757a5de0f4bd891d3b392c44c4f@bitarbeiter.net>

andreas-p/nextcloud-server,andreas-p/nextcloud-server,nextcloud/server,nextcloud/server,nextcloud/server,andreas-p/nextcloud-server,andreas-p/nextcloud-server,nextcloud/server,andreas-p/nextcloud-server