Fixed typo in MapReduce documentation.
Fixed typo in MapReduce documentation.

influxdata/kapacitor,influxdata/kapacitor,adityacs/kapacitor,yosiat/kapacitor,influxdata/kapacitor,alerta/kapacitor,alerta/kapacitor,alerta/kapacitor,bbczeuz/kapacitor,yosiat/kapacitor,adityacs/kapacitor,influxdb/kapacitor,sputnik13/kapacitor,titilambert/kapacitor,sputnik13/kapacitor,muxinc/kapacitor,influxdb/kapacitor,adityacs/kapacitor,bbczeuz/kapacitor,titilambert/kapacitor,bbczeuz/kapacitor,influxdb/kapacitor,muxinc/kapacitor,yosiat/kapacitor,muxinc/kapacitor,sputnik13/kapacitor,titilambert/kapacitor