libtracker-miner: Handle multiple nfo:belongsToContainer properties to 1 nie:url

Previously we've expected this to be a 1:1 relationship, but it's not always
the case with data containers
libtracker-miner: _NO_STAT breaks in FileNotifier without a GFileInfo

GFileInfo is ABSOLUTELY required in the Crawler, without it the
TrackerFileNotifier will that top level roots have been deleted because the
GFileInfo GQuark does not exist.

This is seen easily by mounting a removable device, indexing, then removing,
then re-inserting that same device.

The check is done later in the TrackerFileNotifier by looking up the qdata
that we set in both conditions below.