[0.11.0] httpjson: panic: runtime error: invalid memory address or nil pointer dereference

[causelove-xyz]

After updating to version 0.11.0 telegraf started crashing at every collection cycle on one of 7 nodes.

Node used httpjson with following configuration:

   [[inputs.httpjson]]
        name='service_activeusers'
        method='GET'
        servers=['http://172.17.0.1:9030/active']

curl call works as expected:

[root@server telegraf]# curl http://172.17.0.1:9030/active
{"count":0}

[root@server telegraf]# telegraf -config /etc/telegraf/telegraf.conf -config-directory /etc/telegraf/telegraf.d
2016/03/16 15:23:45 Starting Telegraf (version 0.11.0)
2016/03/16 15:23:45 Loaded outputs: influxdb
2016/03/16 15:23:45 Loaded inputs: httpjson
2016/03/16 15:23:45 Tags enabled: host=server.example.org
2016/03/16 15:23:45 Agent Config: Interval:10s, Debug:false, Quiet:false, Hostname:"server.example.org", Flush Interval:10s
panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xb code=0x1 addr=0x10 pc=0x6f80ad]

goroutine 31 [running]:
net/http.(*Client).doFollowingRedirects(0x0, 0xc820094380, 0x128b2a8, 0x0, 0x0, 0x0)
    /usr/local/go/src/net/http/client.go:313 +0x6d
net/http.(*Client).Do(0x0, 0xc820094380, 0x4ccc78, 0x0, 0x0)
    /usr/local/go/src/net/http/client.go:175 +0x9c
github.com/influxdata/telegraf/plugins/inputs/httpjson.RealHTTPClient.MakeRequest(0x0, 0xc820094380, 0x17b3b20, 0x0, 0x0)
    /home/ubuntu/telegraf-build/src/github.com/influxdata/telegraf/plugins/inputs/httpjson/httpjson.go:59 +0x37
github.com/influxdata/telegraf/plugins/inputs/httpjson.(*HttpJson).sendRequest(0xc82016ebb0, 0xc8200ad1e0, 0x1d, 0x0, 0x0, 0x0, 0x0, 0x0)
    /home/ubuntu/telegraf-build/src/github.com/influxdata/telegraf/plugins/inputs/httpjson/httpjson.go:263 +0x877
github.com/influxdata/telegraf/plugins/inputs/httpjson.(*HttpJson).gatherServer(0xc82016ebb0, 0x7ff3f61ada18, 0xc82016dd00, 0xc8200ad1e0, 0x1d, 0x0, 0x0)
    /home/ubuntu/telegraf-build/src/github.com/influxdata/telegraf/plugins/inputs/httpjson/httpjson.go:178 +0x5f
github.com/influxdata/telegraf/plugins/inputs/httpjson.(*HttpJson).Gather.func1(0xc8200ab030, 0xc82016ebb0, 0x7ff3f61ada18, 0xc82016dd00, 0xc820016de0, 0xc8200ad1e0, 0x1d)
    /home/ubuntu/telegraf-build/src/github.com/influxdata/telegraf/plugins/inputs/httpjson/httpjson.go:145 +0x7e
created by github.com/influxdata/telegraf/plugins/inputs/httpjson.(*HttpJson).Gather
    /home/ubuntu/telegraf-build/src/github.com/influxdata/telegraf/plugins/inputs/httpjson/httpjson.go:148 +0x3ab

[sparrc]

ugh, this is why I hate methods without pointer receivers, I'll have a fix for this soon