TrackerMinerFS: Perform one mtime query per folder.
TrackerMinerFS: Perform one mtime query per folder.

Now that crawling/processing order is guaranteed to have all items
in one folder to be handled together, perform a mtime query per folder,
and compare against these results.

hoheinzollern/tracker,outofbits/tracker,hoheinzollern/tracker,hoheinzollern/tracker,outofbits/tracker,hoheinzollern/tracker,outofbits/tracker,outofbits/tracker,outofbits/tracker,hoheinzollern/tracker,hoheinzollern/tracker,outofbits/tracker,hoheinzollern/tracker,outofbits/tracker