Align README with the code

plugins/inputs/x509_cert/README.md

@@ -9,16 +9,17 @@ file or network connection.
 ```toml
 # Reads metrics from a SSL certificate
 [[inputs.x509_cert]]
-  ## List of local SSL files
-  # files = ["/etc/ssl/certs/ssl-cert-snakeoil.pem"]
-  ## List of servers
-  # servers = ["tcp://example.org:443"]
+  ## List certificate sources
+  # sources = ["/etc/ssl/certs/ssl-cert-snakeoil.pem", "https://example.org"]
+
   ## Timeout for SSL connection
   # timeout = 5
+
   ## Optional TLS Config
   # tls_ca = "/etc/telegraf/ca.pem"
   # tls_cert = "/etc/telegraf/cert.pem"
   # tls_key = "/etc/telegraf/key.pem"
+
   ## Use TLS but skip chain & host verification
   # insecure_skip_verify = false
 ```
@@ -28,8 +29,7 @@ file or network connection.
 
 - `x509_cert`
   - tags:
-    - `server` (only if `servers` parameter is defined)
-    - `file` (only if `files` parameter is defined)
+    - `source` - source of the certificate
   - fields:
     - `expiry` (int, seconds)
     - `age` (int, seconds)
@@ -40,6 +40,6 @@ file or network connection.
 ### Example output
 
 ```
-x509_cert,server=google.com:443,host=myhost age=1753627i,expiry=5503972i,startdate=1516092060i,enddate=1523349660i 1517845687000000000
-x509_cert,host=myhost,file=/path/to/the.crt age=7522207i,expiry=308002732i,startdate=1510323480i,enddate=1825848420i 1517845687000000000
+x509_cert,host=myhost,source=https://example.org age=1753627i,expiry=5503972i,startdate=1516092060i,enddate=1523349660i 1517845687000000000
+x509_cert,host=myhost,source=/etc/ssl/certs/ssl-cert-snakeoil.pem age=7522207i,expiry=308002732i,startdate=1510323480i,enddate=1825848420i 1517845687000000000
 ```

plugins/inputs/x509_cert/x509_cert.go

@@ -18,7 +18,7 @@ import (
 )
 
 const sampleConfig = `
-  ## List of servers and local SSL files
+  ## List certificate sources
   # sources = ["/etc/ssl/certs/ssl-cert-snakeoil.pem", "tcp://example.org:443"]
 
   ## Timeout for SSL connection