tracker-miner-fs: respect the crawling-interval setting
tracker-miner-fs: respect the crawling-interval setting

mtime checks will only be performed on configuration directories
according to this setting.

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