libtracker-miner: Ignore mtime difference of less than 2 seconds
libtracker-miner: Ignore mtime difference of less than 2 seconds

FAT stores timestamps with 2 second granularity.

Fixes NB#287278.

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