libtracker-miner: Hook up directly to pools' state
libtracker-miner: Hook up directly to pools' state

This way the miner is able to resume/pause as the different
task pools notify on ::limit-reached, instead of relying
on the pertinent item_queue_handlers_set_up() call at the
right time.

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