Change perms from 0400 to 0600 for acl-token

[lkysow]

If the acl-init command is re-run, it needs to be able to overwrite the
previously written acl-token file.

In some testing, the service-init init container has later commands fail. Then Kubernetes restarts the init container and it continuously fails with the error:

Error writing token to file "/consul/service/acl-token": open /consul/service/acl-token: permission denied

because that file has already been written but it has 0400 permissions so can't be overwritten.

To reproduce, edit mesh-gateway-deployment:

                ls -la /consul/service
                {{- if (or .Values.global.acls.manageSystemACLs .Values.global.bootstrapACLs) }}
                consul-k8s acl-init \
                  -secret-name="{{ template "consul.fullname" . }}-mesh-gateway-acl-token" \
                  -k8s-namespace={{ .Release.Namespace }} \
                  -token-sink-file=/consul/service/acl-token
                {{ end }}
                exit 1

The first run-through will write the token. Subsequent run throughs will always fail.

[ishustava]

@lkysow This change looks good. It'd be good to add a test or an assertion to check file permissions since this was a bug. I think your comment pretty much covers the intention behind it, but just to make sure it won't be overlooked in the future.

[lkysow]

Absolutely, i've added a test for this!

[ishustava]

Looks great! Thanks for adding a test!