Duplicate entries for servers with certs and CA with x509_cert

[adrianlzt]

Relevant telegraf.conf:

[[inputs.x509_cert]]
  sources = ["https://google.es:443"]
  insecure_skip_verify = true

System info:

Telegraf 1.8.2 (git: HEAD 996a91f)

Steps to reproduce:

1. telegraf/telegraf -config test.conf -test

Expected behavior:

Some tag to distinguish between the cert of the server and the CAs

Actual behavior:

Same tags for two different certs

> x509_cert,host=archer,source=https://google.es:443 age=1778537i,enddate=1545722940i,expiry=5479062i,startdate=1538465340i 1540243877000000000
> x509_cert,host=archer,source=https://google.es:443 age=42759035i,enddate=1639526442i,expiry=99282564i,startdate=1497484842i 1540243877000000000

Additional info:

We can see the two certs with, for example, gnut-tls:

- Got a certificate list of 2 certificates.
- Certificate[0] info:
 - subject `CN=*.google.es,O=Google LLC,L=Mountain View,ST=California,C=US', issuer `CN=Google Internet Authority G3,O=Google Trust Services,C=US', serial 0x359fc6504265b421, RSA key 2048 bits, signed using RSA-SHA256, activated `2018-10-02 07:29:00 UTC', expires `2018-12-25 07:29:00 UTC', pin-sha256="DbEsCd/bn9gwI2cMqQ0BElz8wjP5WXjX7fuZs1JJf/8="

- Certificate[1] info:
 - subject `CN=Google Internet Authority G3,O=Google Trust Services,C=US', issuer `CN=GlobalSign,O=GlobalSign,OU=GlobalSign Root CA - R2', serial 0x01e3a9301cfc7206383f9a531d, RSA key 2048 bits, signed using RSA-SHA256, activated `2017-06-15 00:00:42 UTC', expires `2021-12-15 00:00:42 UTC', pin-sha256="f8NnEFZxQ4ExFOhSN7EiFWtiudZQVD2oY60uauV/n78="

[danielnelson]

I think this will be fixed in 1.8.3 by #4873. Here is the output from the release-1.8 branch:

> x509_cert,common_name=*.google.es,country=US,locality=Mountain\ View,organization=Google\ LLC,province=California,source=https://google.es:443 age=1779598i,enddate=1545722940i,expiry=5478001i,startdate=1538465340i 1540244939000000000
> x509_cert,common_name=Google\ Internet\ Authority\ G3,country=US,organization=Google\ Trust\ Services,source=https://google.es:443 age=42760096i,enddate=1639526442i,expiry=99281503i,startdate=1497484842i 1540244939000000000