Improve query performance in the AggregationIterator by calling .hasNext() on the downsampler instead of letting it build a giant exception string that we're just tossing in the bit bucket.
Improve query performance in the AggregationIterator by calling
.hasNext() on the downsampler instead of letting it build a
giant exception string that we're just tossing in the bit bucket.

Signed-off-by: Chris Larsen <83037b211e1d109d6858769a113e269c3139ffd3@yahoo-inc.com>

ShefronYudy/opentsdb,andyflury/opentsdb,MadDogTechnology/opentsdb,eswdd/opentsdb,eswdd/opentsdb,OpenTSDB/opentsdb,OpenTSDB/opentsdb,MadDogTechnology/opentsdb,ShefronYudy/opentsdb,alienth/opentsdb,OpenTSDB/opentsdb,MadDogTechnology/opentsdb,andyflury/opentsdb,alienth/opentsdb