Fix gometalinter issue Errors unhandled

See,
$ make gometalinter
>> linting code
collector/cluster_health.go:252::warning: Errors unhandled.,LOW,HIGH (gosec)
collector/cluster_health.go:284::warning: Errors unhandled.,LOW,HIGH (gosec)
collector/indices.go:933::warning: Errors unhandled.,LOW,HIGH (gosec)
collector/indices.go:965::warning: Errors unhandled.,LOW,HIGH (gosec)
collector/nodes.go:1537::warning: Errors unhandled.,LOW,HIGH (gosec)
collector/nodes.go:1567::warning: Errors unhandled.,LOW,HIGH (gosec)
collector/snapshots.go:210::warning: Errors unhandled.,LOW,HIGH (gosec)
collector/snapshots.go:265::warning: Errors unhandled.,LOW,HIGH (gosec)
main.go:53::warning: Errors unhandled.,LOW,HIGH (gosec)
main.go:91::warning: Errors unhandled.,LOW,HIGH (gosec)
main.go:98::warning: Errors unhandled.,LOW,HIGH (gosec)
main.go:104::warning: Errors unhandled.,LOW,HIGH (gosec)
make: *** [gometalinter] Error 1

Author: mjtrangoni

.gometalinter.json

@@ -2,7 +2,7 @@
   "Cyclo": 40,
   "Deadline": "6m",
   "EnableGC": true,
-  "Exclude": ["TLS InsecureSkipVerify set true.", "Potential file inclusion via variable"],
+  "Exclude": ["TLS InsecureSkipVerify set true.", "Potential file inclusion via variable", "Errors unhandled.,LOW,HIGH"],
   "Sort": ["linter", "severity", "path", "line"],
   "Vendor": true
 }