Add secure connection support to graphite output (#2602)

etc/telegraf.conf

@@ -270,6 +270,13 @@
 #   template = "host.tags.measurement.field"
 #   ## timeout in seconds for the write connection to graphite
 #   timeout = 2
+#
+#   ## Optional SSL Config
+#   ssl_ca = "/etc/telegraf/ca.pem"
+#   ssl_cert = "/etc/telegraf/cert.pem"
+#   ssl_key = "/etc/telegraf/key.pem"
+#   ## Use SSL but skip chain & host verification
+#   insecure_skip_verify = false
 
 
 # # Send telegraf metrics to graylog(s)