libtracker-miner: Optimize TrackerFileSystem insertions/deletions
libtracker-miner: Optimize TrackerFileSystem insertions/deletions

We rely on the crawler to provide files in-order, so don't unnecessarily
try to reparent child nodes that were added earlier. Also optimize
insertion where a parent is provided.

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