Ignore a RowSeq when it's added out of order to a Span.
Ignore a RowSeq when it's added out of order to a Span.

This allows the TSD to gracefully skip over overlapping rows.

Change-Id: I7f330be9048a932dd95acdc7fb87d97907b13b73

kidaa/opentsdb,sidhhu/opentsdb,andyflury/opentsdb,eswdd/opentsdb,MadDogTechnology/opentsdb,OpenTSDB/opentsdb,MadDogTechnology/opentsdb,ShefronYudy/opentsdb,OpenTSDB/opentsdb,alienth/opentsdb,eswdd/opentsdb,sidhhu/opentsdb,johann8384/opentsdb,andyflury/opentsdb,kidaa/opentsdb,alienth/opentsdb,johann8384/opentsdb,OpenTSDB/opentsdb,ShefronYudy/opentsdb,MadDogTechnology/opentsdb