Heka graph Y-axis scales to 1 due to AggregatorFilter

[shaunwarman]

Unsure as to why the Heka graph's Y-axis jumps to size of 1 when data comes back empty in the AggregatorFilter responses during polling...

{"annotations":{}}
{"time":1463241600,"rows":48,"columns":6,"seconds_per_row":300,"column_info":[{"name":"100","unit":"count","aggregation":"sum"},{"name":"200","unit":"count","aggregation":"sum"},{"name":"300","unit":"count","aggregation":"sum"},{"name":"400","unit":"count","aggregation":"sum"},{"name":"500","unit":"count","aggregation":"sum"},{"name":"Unknown","unit":"count","aggregation":"sum"}]}
0   0   0   0   0   0
0   0   0   0   0   0
0   0   0   0   0   0
0   0   0   0   0   0
0   0   0   0   0   0
0   0   0   0   0   0

...