Fix calling reduceFunction in reduceSeries
Fix calling reduceFunction in reduceSeries

Before it was only sending all the series as `args[1]`, however each series needs to be passed as an arg.
Use same way graphite-web see graphite-project/graphite-web#1265

raintank/graphite-api,raintank/graphite-api,brutasse/graphite-api,rackerlabs/graphite-api,raintank/graphite-api,brutasse/graphite-api,winguru/graphite-api,rackerlabs/graphite-api,winguru/graphite-api