Remove duplicate import
Remove duplicate import

pkg/issuer/venafi/client/venaficlient_test.go:25:2: package "k8s.io/client-go/listers/core/v1" is being imported more than once (ST1019)
pkg/issuer/venafi/client/venaficlient_test.go:26:2: other import of "k8s.io/client-go/listers/core/v1"

Signed-off-by: Richard Wall <c2866c0eefadc742fd429365a658dfba4f801ca3@jetstack.io>

jetstack-experimental/cert-manager,cert-manager/cert-manager,cert-manager/cert-manager,jetstack-experimental/cert-manager,jetstack/cert-manager,cert-manager/cert-manager,jetstack/cert-manager,jetstack-experimental/cert-manager,jetstack/cert-manager