Return clierror.Error on any error

[pPrecel]

Description

Changes proposed in this pull request:

• return every error as clierror.Error to diplay errors always in the same way

before:

go run main.go alpha kubeconfig gen --serviceaccount t

if any flags in the group [serviceaccount clusterrole] are set they must all be set; missing [clusterrole]

after:

go run main.go alpha kubeconfig gen --serviceaccount t

Error:
  failed to execute command

Error Details:
  if any flags in the group [serviceaccount clusterrole] are set they must all be set; missing [clusterrole]