Skip FailedStorage in background scan
Skip FailedStorage in background scan

The background job that scans storages must skip failed storages to
avoid potential exceptions, especially when the failed storage comes
from a shared storage where the source is not accessible.

Signed-off-by: Morris Jobke <7f550a9f4c44173a37664d938f1355f0f92a47a7@morrisjobke.de>

Ardinis/server,Ardinis/server,michaelletzgus/nextcloud-server,endsguy/server,pixelipo/server,Ardinis/server,pixelipo/server,endsguy/server,pixelipo/server,michaelletzgus/nextcloud-server,andreas-p/nextcloud-server,endsguy/server,andreas-p/nextcloud-server,michaelletzgus/nextcloud-server,andreas-p/nextcloud-server,Ardinis/server,andreas-p/nextcloud-server,Ardinis/server,nextcloud/server,endsguy/server,nextcloud/server,nextcloud/server,endsguy/server,andreas-p/nextcloud-server,pixelipo/server,nextcloud/server,pixelipo/server,michaelletzgus/nextcloud-server