ntp plugin crash

[gmr]

A parse error in the ntp plugin caused a telegraf agent to crash.

Relevant telegraf.conf:

[[inputs.ntpq]]
#   ## If false, set the -n ntpq flag. Can reduce metric gather time.
#   dns_lookup = true

System info:

Telegraf - version 0.13.1
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=14.04
DISTRIB_CODENAME=trusty
DISTRIB_DESCRIPTION="Ubuntu 14.04.5 LTS"

Steps to reproduce:

I'm guessing an unexpected response from the call the agent makes to grab NTP info causes the crash to happen.

Expected behavior:

Agent doesn't crash

Actual behavior:

Agent Crashes

Additional info:

2016/08/15 09:46:00 ERROR ntpq: parsing int: 77.759
panic: runtime error: index out of range

goroutine 2202595 [running]:
panic(0x107ebc0, 0xc820010080)
    /usr/local/go/src/runtime/panic.go:481 +0x3e6
github.com/influxdata/telegraf/plugins/inputs/ntpq.(*NTPQ).Gather(0xc8204da660, 0x7f5ecebaa368, 0xc82078c000, 0x0, 0x0)
    /home/ubuntu/telegraf-build/src/github.com/influxdata/telegraf/plugins/inputs/ntpq/ntpq.go:175 +0xc90
github.com/influxdata/telegraf/agent.gatherWithTimeout.func1(0xc820558120, 0xc8201d0c60, 0xc82078c000)
    /home/ubuntu/telegraf-build/src/github.com/influxdata/telegraf/agent/agent.go:174 +0x73
created by github.com/influxdata/telegraf/agent.gatherWithTimeout
    /home/ubuntu/telegraf-build/src/github.com/influxdata/telegraf/agent/agent.go:175 +0xe0

[sparrc]

thanks for the report, I was able to reproduce in a unit test and I'll have a fix up in master shortly