Bug / Feature Request: Cluster SBD Error'ing (when not present)

[ashleyprimo]

I have noticed that when operating the exporter on a machine that does not have sbd setup the following set of errors are seen repeatedly:

2019/10/11 15:14:12 [INFO]: Reading cluster SBD configuration..
2019/10/11 15:14:12 [ERROR] Could not open sbd config file open /etc/sysconfig/sbd: no such file or directory

There should maybe be a check such as

if _, err := os.Stat("/etc/sysconfig/sbd"); os.IsNotExist(err) {
	log.Println("[INFO]: SBD is not present... skipping.")
} else {

}

This would give a single output of 0000/00/00 00:00:00 [INFO]: SBD is not present... skipping. instead of continually repeating an error in the absence of sbd. :)

[MalloZup]

@ashleyprimo ok I have looked at your PR. Make sense thx for this.

[MalloZup]

done

[MalloZup]

thx!