Fix evaluating ATA Error Count: 0 as a warning

[usrflo]

Without the definition of an ata_errors warning level the smart output of ATA Error Count: 0 ends up in ata_errors is non-zero (0)[/dev/sda] in the output.
So the zero case needs to be excluded explicitly checking ATA error counts.

[Napsty]

Thanks for the PR! Makes sense to me.
Can you just show the current behavior (execution and output of the plugin) in such a situation?

[usrflo]

The output before excluding 0:

$ /usr/bin/sudo /usr/lib/nagios/plugins/check_smart.pl -g '/dev/sd[a-d]' -i 'ata' -w 'Reallocated_Sector_Ct=4,Runtime_Bad_Block=4,Uncorrectable_Error_Cnt=2,Reallocated_Event_Count=2' --skip-self-assessment
WARNING: [/dev/sda] - [/dev/sda] - ata_errors is non-zero (0)[/dev/sda] -  --- [/dev/sdc] - [/dev/sdc] - ata_errors is non-zero (0)[/dev/sdc] -  --- [/dev/sdd] - [/dev/sdd] - ata_errors is non-zero (0)[/dev/sdd] -  --- [/dev/sdb] - Device is clean

The output after excluding 0 via this patch:

$ /usr/bin/sudo /usr/lib/nagios/plugins/check_smart.pl -g '/dev/sd[a-d]' -i 'ata' -w 'Reallocated_Sector_Ct=4,Runtime_Bad_Block=4,Uncorrectable_Error_Cnt=2,Reallocated_Event_Count=2' --skip-self-assessment
OK: [/dev/sda] - Device is clean --- [/dev/sdb] - Device is clean --- [/dev/sdc] - Device is clean --- [/dev/sdd] - Device is clean|

[Napsty]

LGTM, thanks again!
Allow me some time for a version bump and new release.