Fix reloader error message to only print on actual error

[vjsamuel]

Error message for runnerFactory.Create(c) should only be printed when there is no other runner for the same config that is already active.

When there is a runner active for a prospector, log prospector would return:

2017/08/31 09:17:53.951071 registrarcontext.go:31: ERR Error creating prospector: Can only start a prospector when all related states are finished: {Id: Finished:false Fileinfo:0xc420491ba0 Source:/var/lib/docker/containers/3108a14952a84074e6a28eeb8af17348860cd26f0b40550cd18ac3883570712f/3108a14952a84074e6a28eeb8af17348860cd26f0b40550cd18ac3883570712f-json.log Offset:51008 Timestamp:2017-08-31 09:17:43.943364786 +0000 UTC TTL:-1ns Type:log FileStateOS:310155-2049}

this being printed each time is incorrect as the prospector is already running and is not being reloaded each time. the error should be printed only if there is no active runner and a factory.Create fails.

[elasticmachine]

Can one of the admins verify this patch?

[ruflin]

Thanks for fixing. I think there is even somewhere a Github issue for that.

Waiting for green.

[ruflin]

jenkins, test it