streamthinca: small performance tweak

- the SNR segments are stored with float boundaries, so be careful to
  convert things to floats when testing to see if they are covered by the
  segments to avoid repeated type casts inside the internal bisection
  search comparison operation

gstlal-inspiral/python/streamthinca.py

@@ -225,7 +225,7 @@ class backgroundcollector(object):
 		flushed_ids = set(index)
 		background_ids = self.timeshifted_coincs & flushed_ids
 		self.timeshifted_coincs -= flushed_ids
-		background_ids |= set(event_id for event_id in self.zerolag_singles & flushed_ids if index[event_id].end in two_or_more_instruments)
+		background_ids |= set(event_id for event_id in self.zerolag_singles & flushed_ids if float(index[event_id].end) in two_or_more_instruments)
 		self.zerolag_singles -= flushed_ids
 		return [event for event in map(index.__getitem__, background_ids) if event.snr >= snr_min]