Influxcli precision hardcoded to n

[kostasb]

Looks like InfluxCLI always sends the parameter 'precision' set to 'n'.

In the following example "seconds" precision is specified but the parameter sent to InfluxDB is still "n"

Connected to http://localhost:8086 version 0.14.0~n201605190800
InfluxDB shell version: 0.14.0~n201605190800
> create database test
> use test
Using database test
> precision s
> insert a,tag="2049" value=2049 2524607999

Logs:
[httpd] 2016/05/19 15:59:33 127.0.0.1 - - [19/May/2016:15:59:33 +0000] POST /write?consistency=any&db=test&precision=n&rp= HTTP/1.1 204 0 - InfluxDBShell/0.14.0~n201605190800 ad81dadf-1dda-11e6-8053-000000000000 40.686496ms

https://github.com/influxdata/influxdb/blob/master/cmd/influx/cli/cli.go#L512

@e-dard @corylanou