Use "value" as the field name also in graphite

[cannium]

#2412 says it's fixed but actually not.

[liyichao]

Yeah, it's not fixed.

[otoolep]

Thanks @cannium -- the tests also need to be updated. Can you do that? If not, I will do so.

[otoolep]

Specifically:

--- FAIL: Test_ServerSingleGraphiteIntegration_NoDatabase (3.29s)
    server_integration_test.go:1944: Graphite Connection String: 127.0.0.1:0
    server_integration_test.go:88: Creating cluster of 1 nodes for test graphite integration
    server_integration_test.go:97: Test graphite integration: using tmp directory "/tmp/influxdb-804192646/broker-integration-test" for brokers
    server_integration_test.go:98: Test graphite integration: using tmp directory "/tmp/influxdb-804192646/data-integration-test" for data nodes
    server_integration_test.go:136: http://:37585
    server_integration_test.go:1971: Writing data
    server_integration_test.go:1986: Test "graphite integration" failed, expected: {"results":[{"series":[{"name":"cpu","columns":["time","cpu"],"values":[["2015-05-12T22:38:35Z",23.456]]}]}]}, got: {"results":[{"series":[{"name":"cpu","columns":["time","value"],"values":[["2015-05-12T22:38:35Z",23.456]]}]}]}

and perhaps a couple others.

[cannium]

I fixed the tests, but I seems to hit some other bug. @otoolep Any ideas?

[otoolep]

That's a known issue, we're tracking down. #2517

I kicked the build, let's see if it goes green.

[otoolep]

@corylanou -- can you also review?

[otoolep]

+1 from me, on green build -- thanks @cannium

[corylanou]

Looks good. +1. Thanks!

[toddboom]

@cannium thanks!